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R/E/P => Klaus Heyne's Mic Lab => Topic started by: klaus on June 05, 2017, 12:49:52 pm

Title: The Myth of the Accurate Microphone
Post by: klaus on June 05, 2017, 12:49:52 pm
Can we really make a distinction between “colored” and “accurate” microphones? Who decides what mic falls into what category, and on what basis?

Proponents invariably define an “accurate” mic as one that does not add to or take away from, or in any other way alter the musical event: what goes in comes back out, exactly and precisely.

I think the premise that such a microphone currently exists is false. "Accurate" means that no audible or measurable difference could ever be claimed between brands and models, because, by definition, any “accurate” mic you chose would sound exactly like the next, given the same polar pattern. 

The reality looks different. Some like the sound of one mic they believe is 'accurate'. Others like the sound of a different mic, with the same claim of accuracy. But if there is a 'sound' (i.e. color), which one then is accurate?

It’s frustrating to read discussions of the term 'accurate' in forum posts, because quasi-scientific arguments are used to prove something that, in my opinion, is not currently provable, given the available (and rather primitive) parameters available to quantify data related to sound.

End (or start) of discussion...

Update: post #50 is brilliant, and I have copied it here, for those who do not have the time or patience to read all the others:

"Good sound" is not (for me) an objective that gets completed, but rather a lifelong pursuit of a feeling. I hope that each record I make is better (read: more emotionally-resonant) than the last, for the rest of my career. I doubt I will ever feel like that mission has been wholly and indisputably accomplished. In that sense, there is no "ballpark."

And much like there's no objective metric to determine the "best guitar player," I feel there's no objective metric (or set of metrics) that can meaningfully determine the "best (read: 'most accurate') microphone."

Because things which can be measured are almost always relatively unimportant in the context of work designed foremost to move someone emotionally.

For example: There are many people who can jump higher, run faster, have higher IQs, and have more symmetrical facial features than I. My wife may even know some of those people, but she loves me. Why? Emotion is profoundly illogical. Those objective metrics have a laughably-poor correlation to why my wife might've fallen in love with me. Broadly speaking, to contrive to explain an emotional response in terms of available objective metrics is folly. For one thing, it opens us up to the cognitive biases of anchoring/focalism, the availability heuristic, ambiguity effect and the base-rate fallacy, among others. Simply put: most of what moves us emotionally cannot be measured, and that puts us at risk of over-emphasizing things which can, when making judgments.

And so it is with microphones. If I listen to a recording of a great vocalist on a great U47 and instantly feel an emotional connection to the performance--more than the same performance into a microphone that measures quieter, flatter, more extended-- then which do I choose?

Do I choose the person with the higher IQ who runs faster? Or do I choose the partner with whom I've fallen in love?

Not everything that matters can be justified through empirical means. This is especially so in matters of emotion--and my goal with creating or capturing music is always to elicit within the listener an emotional response.


Brad Allen Williams

Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on June 06, 2017, 11:37:40 am
Until a microphone can duplicate the locational sensing of the human ear none of them are even remotely accurate. A person with only one working ear can point and determine a sound's location easily in a 360 degree field.

At this point of microphone design we are at the same point as the romantic painters were in the 17th century before the advent of modern photography. Yes, those paintings are very emotionally pleasing to look at but are not in any sense accurate.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on June 13, 2017, 11:34:50 am
Even if you isolate one variable-- say "frequency response"-- invariably, other variables creep in.

One microphone might be "perfectly flat" in an anechoic chamber directly on-axis at a distance of 1m, but what happens when you're 90 degrees off-axis? What happens when you're 10 cm away, or 20m away?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on August 01, 2017, 12:32:51 am
Well like any other measuring tool, mics are accurate within certain tolerances and limits, but the key is understanding those limits to produce very accurate results.

I suspect at least some of the distrust of mics as accurate comes from ignorance rather than knowledge. In the field of  acoustic measurement, there have been extraordinarily accurate mics around, such as from B and K, for many decades. Of course there are trade offs, such as frequency response vs S/N, and directionality vs proximity effect and polar pattern linearity, but the skilled person knows these limitations and carefully works within them.

Tim 
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on August 01, 2017, 03:30:15 am
If what you say were correct, why don't more people use B&K/DPA mics? Their static specs are certainly hard to beat: s/n and frequency linearity are exemplary.
Yet, they are not considered "musical" by most artists, music engineers and producers, and rarely find usage in recording studios.

What may be missing here?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on August 01, 2017, 04:49:27 am
Part of what's missing is perhaps a common understanding of what we mean by terms.

So what makes  a microphone  "musical" or "non musical"? What is meant by these terms in relation to mics or indeed any audio gear?

Tim

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on August 01, 2017, 10:32:33 am
I already stated in my opening post that the term "accurate" is problematic, judging from the success, or lack of, of mics that claim to be accurate.

So, if such mic does not really exist, maybe a term like "musical" comes closer to what we ultimately envision* - a mic that delivers music's emotional content to the listener, connecting in ways "accurate" mics seem not to be able to.

* maybe I am in the minority here. But I still try to engage my right brain hemisphere when listening to music, rather than intellectually analyzing what I hear in the moment I hear it.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on August 01, 2017, 06:42:55 pm
People are musical - some more than others. But microphones? Speaker cables?

 
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on August 02, 2017, 10:54:28 am
People are musical - some more than others. But microphones? Speaker cables?

The commonly-measured factors do matter. But I think it's folly to assume we can derive the gestalt of a device by these factors alone.

Two cars can share the same top speed, horsepower and torque, but still offer different driving experiences. One might be enjoyable to drive while the other is less so, and the specifications alone would likely struggle to explain why.

It's important, I think, to acknowledge that microphones aren't strictly documentarian-- they are, in some sense, a tool for creating art (just like guitars or pianos). This remains true even when recording music in the most literal way.

If I'm recording a classical piano recital, my goal is to give to the listener the sense, as near as possible, that they're in the hall with the performer enjoying the concert in person. Since recording technology is still so far from replicating live performance in an indistinguishable manner, sometimes the non-literal is relied upon to help bring the illusion closer to the subjective ideal. This is where recording becomes an art that relies upon science, rather than science, strictly speaking.

And in art--even that art which relies upon science--a subjective impression (i.e. "this microphone sounds more musical to me") is certainly admissible. In fact, I'd argue that a keen grasp of the subjective is a big part of what separates a "skilled and experienced expert" from a "person with some training and equipment."
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on August 02, 2017, 12:46:37 pm
Well said, and to the point. Thanks!
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on August 03, 2017, 12:38:58 am

...And in art--even that art which relies upon science--a subjective impression (i.e. "this microphone sounds more musical to me") is certainly admissible.

 Sure it's admissible but to me an isolated comment like "this microphone sounds more musical to me" communicates merely that "I like what I'm hearing".

BTW enjoyed your guitar playing on "More than you know"  "Steppin' Out" and "Sly".

Tim
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on August 03, 2017, 03:46:16 am
Communicating "merely" that you like what you're hearing- not enough?
You think there's more? If so, what is it and what mic transports it?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on August 03, 2017, 04:21:37 am
You mentioned musicians, producers, engineers considering flat mics - and you specifically mentioned B & K and DPA mics - not "musical".
But they would probably happily use a KM184 in certain situations where neutrality is considered important and the acoustics allow. As I understand it, the KM184's response  would be similar to that of a 1/2" omni  B & K measurement mic. What would be the difference in your opinion?

 
Title: Re: The Myth of the Accurate Microphone
Post by: BluegrassDan on September 03, 2017, 06:08:04 pm
Who wants to hear a singer's every slobber, lip smack, and snot bubble afforded by an "accurate" mic and/or "transparent" preamp? Microphones are best when they represent the capture of a musical performance in a pleasing way.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on September 04, 2017, 09:36:11 am
Is  there a mic out there which is insensitive to "slobbers",  "lip smacks" and "snot bubbles" but let all the "musicality" through? Now that's one "intelligent" microphone.  What's its make and model number?
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on September 04, 2017, 11:23:47 am
If those natural sounds are so offensive, no one would have bothered singing until modern processing electronics were available.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on September 04, 2017, 12:00:36 pm
(...) As I understand it, the KM184's response would be similar to that of a 1/2" omni  B & K measurement mic. What would be the difference in your opinion?

The difference may be between truth and myth. Can you cite a source for your 'understanding'?
Title: Re: The Myth of the Accurate Microphone
Post by: David Satz on September 24, 2017, 04:40:02 pm
In addition, the B & K measurement microphone is a pressure transducer with an omnidirectional pickup pattern, while the KM 184 is about 50% a pressure-gradient transducer and only about 50% a pressure transducer, resuting in a cardioid pickup pattern. No one would ever mistake the one microphone for the other, I think, even if the free-field, 0-degree frequency response of both microphones was identical (which I'm rather certain it is not).

--best regards
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 08, 2017, 08:50:12 pm
In addition, the B & K measurement microphone is a pressure transducer with an omnidirectional pickup pattern, while the KM 184 is about 50% a pressure-gradient transducer and only about 50% a pressure transducer, resuting in a cardioid pickup pattern...

 My apologies, I meant the omni capsule of course, the KM183. 
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 08, 2017, 09:07:14 pm
If what you say were correct, why don't more people use B&K/DPA mics? Their static specs are certainly hard to beat: s/n and frequency linearity are exemplary.
Yet, they are not considered "musical" by most artists, music engineers and producers, and rarely find usage in recording studios.

What may be missing here?

Perhaps that measurement mics are calibrated (and that may mean hand selected samples) to a very strict standard, with something like a frequency response accurate within 0.3db. That will cost the company and therefore the customer more money. For audio work that sort of accuracy isnt normally required. Of course the same company could also market essentially the same mics but without such stringent specs. I cant be sure. Hard to find such information on the net.

Certainly cardioid mics are often  more desirable in an audio recording vs omnis and especially in PA situations. But as we know in this case, some  accuracy is traded off for the more useful cardioid type pattern with its selected rejection of unwanted sounds and less feedback susceptibility. This seems to reinforce the first point that in audio recording situations, some accuracy trade off is acceptable where it wouldnt be for strict measurement requirements.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on November 10, 2017, 11:34:41 am
Perhaps that measurement mics are calibrated (and that may mean hand selected samples) to a very strict standard, with something like a frequency response accurate within 0.3db.

The thing is, when discussing such a calibration against a reference, we must (at a minimum) answer the following questions:

"at what distance?"
"at what angle of incidence?

And when we do answer these questions, we must also understand the limited scope and relevance of the information presented.

If a microphone is calibrated to be "accurate within 0.3 dB" at, say, 1m directly on-axis, that's not going to be perfectly correlated with its frequency response at 1cm, or 10m, or at 90 degrees off-axis, or even at ten degrees off-axis.

And outside an anechoic chamber, off-axis coloration will always contribute to the sound of a microphone. Even if a microphone measures completely "flat" in all typical tests, it's still possible that it may perform poorly for music recording.

Subjectively, I've found off-axis characteristics to be one place where some of the better microphones really "earn their stripes," for me. Bleed/spill/leakage from off-axis sources into something like a U87 or U67 is less-often objectionable to me than spill into a lesser microphone, even if the on-axis characteristic of the lesser microphone is acceptable.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 10, 2017, 04:08:03 pm
 We were discussing omni mics.  An omni DPA 1/2" SDC and the omni 1/2" SDC measurement mic equivalent will share an essentially identical polar response. The only difference between the two mics will be that the measurement mic is calibrated to a  higher degree of  accuracy. Again, will that higher degree of accuracy make it less "musical"? If so, how? What causes the alleged qualitative difference to appear?

On your last point about the desirability of well behaved off axis response in say a cardioid mic I totally agree, but how does that relate  to the claim that a measurement mic is by definition  less "musical" - whatever that means? Omni mics of course have a better behaved polar response than cardioid types, but regardless, when comparing otherwise identical omnis with omnis  it's of course irrelevent.

I suggested two reasons why measurement mics are less common in non measurement applications. You didnt acknowledge or address either point but made a point about polar patterns which is true but seems irrelevent to the point being discussed.

Tim
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 10, 2017, 07:13:03 pm
I can think of an issue that could make measurement mics inherently unsuitable for music recording: transducer and electronics that are customized for an ultra-linear rendering of single, sequentially fed sine waves.

You get that kind of response by using extensive corrective electronic and acoustic measures, which typically move the overall response of such a mic away from simple but musical (and decidedly not linear!) circuitry and capsule geometry.

The all-time greats still widely used today to record music do not measure well at all; look at a graph of an original ELA M251, for example: nothing but valleys and peaks, and audible differences from one mic to the next. But what seems to slip through quite nicely despite such gross non-linearity (or because of it) is the music.

Or to put it simply: it seems that the more complicated a microphone's circuitry, the less musical. Somehow non-linear musicality trumps the ultra-linear response of measurement mics.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 10, 2017, 08:43:10 pm
I can think of an issue that could make measurement mics inherently unsuitable for music recording: transducer and electronics that are customized for an ultra-linear rendering of single, sequentially fed sine waves.

Again I refer you to the earlier point.  Frequency response  over the audible range within a fraction of a db tolerance has been achieveable in  measurement mics for decades - and without external corrective EQ.  That sort of linearity is not normally needed for music and voice recording - but will hardly make recordings made with such a mic "less musical". Some people do indeed use measurement mics for recording. I personally think they are wasting money on a level of technical accuracy that nobody will appreciate just listening to music.

So  using a measurement mic and amp combination that has even more accuracy (ultra linear) at certain spot frequencies for a music recording would be even more pointless, and even more  needless expense.

Some mics are more suited to different tasks. The ELA M251 might have some roughness in response (I havent seen a graph or used one) but I suspect it's a very useable mic not because of some  roughness in response but in spite of it. And the response wont be very rough or nobody would use it for high quality work.

Then there's the issue of response graphs that have been "corrected" or "smoothed" We could discuss that separately...

And why  only talk about condenser mics? If roughness of response made a mic more "musical" then high quality condenser mics would not have needed inventing. Cheap, garden variety dynamics have bags of non linearity. But we pay more money for an MD441 dynamic which was carefully designed to rival the linearity of a condenser - but doesnt quite get there.

I dont agree that the more complicated the mic's design the less musical. The old AKG D202 had the unusual complication of two transducers. The ELA M250 had two backplates I believe. The U87 has two diaphragms. The new Shure KSM 8 stage dynamic mic is a complicated and more expensive design which achieves pretty flat response, the best absence of proximity effect and smoothest polar pattern in such a mic ever. Before it the whole range of EV "D" mics which aimed for similar performance in a rugged package but which also entailed a more complex design.

The wise old design rule is "as simple as possible - but no simpler"...





   
Title: Re: The Myth of the Accurate Microphone
Post by: Michael O. on November 10, 2017, 10:18:07 pm
I have to agree with KH here: very generally speaking simple proves best. Klaus is talking about simplicity in circuitry, and the EV variable-d design that was mentioned could hardly be more elegant in that regard (no circuitry). They're simply a transducer, a connector, and sometimes a transformer. The vents that create the pattern and avoid the typical proximity effect are innovative and clever, but not complex in their implementation. The corrective electronics he refers to is the sort within a (condenser) mic's internal circuitry (e.g. the hi frequency de-emphasis network in a U87).

If you follow this whole thought experiment to its logical conclusions it all becomes moot. Regardless of the accuracy of any given microphone we would have no perfectly accurate way to then output the recorded sound. And if such an accurate playback medium existed we would need an equally well-suited listening environment along the lines of an anechoic chamber to fully appreciate it (with our imperfect and indivually-tuned ears, at that). So, even if our music went from air, to perfect mic, to perfect circuitry and recording medium, and out of a perfect playback system, we would need particular listening conditions to even begin to accurately discern such a signal path.

But ultimately this all comes down to something completely subjective/aesthetics/personal preference. And to generalize, people certainly seem to gravitate toward non-linearity/coloration/roughness in sound.

One final (or maybe initial) consideration is that in this context "accurate" has no determinate definition.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 11, 2017, 12:00:55 am
I have to agree with KH here: very generally speaking simple proves best. Klaus is talking about simplicity in circuitry, and the EV variable-d design that was mentioned could hardly be more elegant in that regard (no circuitry). They're simply a transducer, a connector, and sometimes a transformer. The vents that create the pattern and avoid the typical proximity effect are innovative and clever, but not complex in their implementation. The corrective electronics he refers to is the sort within a (condenser) mic's internal circuitry (e.g. the hi frequency de-emphasis network in a U87).

Hi Michael, I'm  not sure what you are saying here. Are you saying that Neumann made a mistake in using the internal de emphasis in the almost legendary U87 mic? How could it ever have come to be such a highly regarded mic? BTW I didnt know the U87 had internal corrective EQ. Interesting. Which other mics have similar circuitry?

Quote from: Michael O.
If you follow this whole thought experiment to its logical conclusions it all becomes moot. Regardless of the accuracy of any given microphone...

 but "the myth of the accurate microphone " is the topic of the discussion...

Quote from: Michael O.
we would have no perfectly accurate way to then output the recorded sound. And if such an accurate playback medium existed we would need an equally well-suited listening environment along the lines of an anechoic chamber to fully appreciate it (with our imperfect and indivually-tuned ears, at that). So, even if our music went from air, to perfect mic, to perfect circuitry and recording medium, and out of a perfect playback system, we would need particular listening conditions to even begin to accurately discern such a signal path.

Quite and it puts into perspective the obsession some people have with getting just the right microphone, as if microphone accuracy is a fundamental problem, when in practice, the playback and potential for hugely variable listening conditions is far more problematic if fidelity to the source is our standard.

But ultimately this all comes down to something completely subjective/aesthetics/personal preference.
That's certainly a factor but it depends on the weighting we give it. If people's preference was so widely divergent, group listening to live symphony orchestras would be impossible to please most attendees, as it would be for any group listening activity. Unless a person has a moderate to serious hearing impairment there are good general guidelines as to what most people regard as good, listenable sound. Professional cinemas for example are only able to deliver good acceptable sound to most film goers because they are guided by such parameters and indeed there is a long history of this, with ongoing progress and development.

 
Quote from: Michael O.
And to generalize, people certainly seem to gravitate toward non-linearity/coloration/roughness in sound.

With certain sounds, and in certain musical genres yes but not so much in others. Classical music recording has a long tradition of fidelity to the sound of the performed music although there will always be some disagreement as to what constitutes the ideal listening position, balance of instruments, amount of venue reverberation etc, including listening level, which is also related to Fletcher Munson.

Quote from: Michael O.
One final (or maybe initial) consideration is that in this context "accurate" has no determinate definition.

Well if we limit ourselves to the initial topic of the thread: the accuracy of microphones, we might find there are  indeed objective standards and tests that are empirical and repeatable. Once we confuse this aspect with personal subjective preference - which is to some degree true - and the potentially huge variability of real world listening conditions, both of which you mentioned and are certainly true, we have changed topics. Again I thought the question was the accuracy of microphones.

Tim
Title: Re: The Myth of the Accurate Microphone
Post by: panman on November 11, 2017, 05:16:17 am
Well if we limit ourselves to the initial topic of the thread: the accuracy of microphones, we might find there are  indeed objective standards and tests that are empirical and repeatable. Once we confuse this aspect with personal subjective reference - which is to some degree true - and the potentially huge variability of real world listening conditions, both of which you mentioned and are certainly true, we have changed topics. Again I thought the question was the accuracy of microphones.
Tim

I find this thread has been good so far and good points have been discussed. To me this topic requires a lot of deviations to make any sense at all or how would you make limits to this discussion? Too tight borderlines and what is there to discuss?
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 11, 2017, 01:16:48 pm
One should come to the logical conclusion that accurate microphones do not exist at this point of human development.

Measurement microphones are not in any way accurate as to encoding the reality of what a mammal can detect. Like all microphones they are an air pressure to electron converter with many factors of actual hearing left out, like location sensing and the ability to seperate multiple sounds at the same time.

Yes, measurement microphones use the same technology as recording microphones, diaphram, impedance converter and output stage. There are not any "electronics customized for an ultra linear rendering of single, sequentially fed sine waves". No such specialized amplifiers exist, either they have low THD specs or they do not. Amplifiers do not discriminate between differing wave shapes as long as the bandwidth can accomodate all of them.

After 100+ years of microphone development we are really no closer to that goal than we were 100 years ago. Maybe that's why microphone designs from the 1930's have not yet been bested.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 11, 2017, 09:28:44 pm
One should come to the logical conclusion that accurate microphones do not exist at this point of human development.

Hi Jim,

Of course all mics have their limitations. The question then is "accurate to what degree, and for what task?" The mic is part of a  chain. Typically is it the weak link in that  chain,  in what respect(s) and by how much? We'd need to look at specific real life cases.

Quote from: Jim Williams link
Measurement microphones are not in any way accurate as to encoding the reality of what a mammal can detect. Like all microphones they are an air pressure to electron converter with many factors of actual hearing left out, like location sensing and the ability to seperate multiple sounds at the same time.

The human ear  needs a brain to interpret the raw data. When we make a music recording we leave it to the brain of the unknown listener at home to do the interpreting. To compare the microphone with a mammallian ear PLUS the mammalian brain seems unfair and invalid.The ear on its own has the same basic limitation of a  microphone. It cant "interpret" sound.  That's not its job. (although the human ear does incorporate a basic kind of "limiter" but only to protect it from damage from loud sounds but even there I'm not sure whether or not that mechanism is triggered within the ear itself or by a signal from the brain). Again, when we make a music recording we leave it to the brain of the unknown listener at home to do the interpreting.

Quote from: Jim Williams link
After 100+ years of microphone development we are really no closer to that goal than we were 100 years ago. Maybe that's why microphone designs from the 1930's have not yet been bested.

Again not sure which goal you are talking about. If you mean that we still havent artificially created a mammallian ear and brain that does the same job as well I'd agree. But we were discussing just the microphone as a transducer (and I guess the associated preamp) and its accuracy.
Sure the capacitor mic of the 30's is still the basis of modern day high quality mics. That it hasnt been bested by another design is inconclusive. It doesnt prove that it will or wont be bested in future, or in what respects and by how much.  We  dont know. We will only know if or when it happens.
In the meantime  we could discuss the microphones that we do have today...

Tim

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 12, 2017, 03:14:40 am
(...) when we make a music recording we leave it to the brain of the unknown listener at home to do the interpreting.

In the field of analyzing any of the five senses, there is no reality outside subjective interpretation. So, objectively, nothing happens acoustically beyond and outside of sound reaching us and having an effect on us.

We continue to TRY correlating sound we hear to sound waves we measure, but that is only valid to the extent that it would allow us to identify specific measurable features of sound waves (like gross frequency anomalies) that we can correlate to dissatisfying sound and try to correct and improve it: listening is the corrective, nothing else.

The idea that certain idealized properties of measurements, like a ruler-flat frequency response, would get us closer to satisfying sound remains unprovable. So far, we can only verify by listening whether manipulating parameter x or y just got us closer to an aurally satisfying experience.

Quote
(...) we were discussing just the microphone as a transducer (and I guess the associated preamp) and its accuracy.

 'Accuracy' of a microphone can only be judged by hearing the musical event live, and comparing how close (accurate) the recording of that event comes to that experience. A determination of accuracy can therefore never be derived from any other (non-sensual) experience or method, see above.

Regarding the relatively primitive nature of microphones, even the best ones, compared to our hearing apparatus, I never get tired of citing this example:

Sitting in an auditorium, and listening to a quiet passage of the orchestra, I can tune out the noise of the person sitting next to me rustling her candy wrapper. If I were listening to a recording of this event with a microphone placed where my ear is, I would be royally annoyed by the disturbance.
The brain can analyze sound waves delivered from the ear's sophisticated pathways, and filter out unwanted noise. The relatively primitive rendering of reality by a microphone does not make this possible.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 13, 2017, 11:16:24 pm

...Regarding the relatively primitive nature of microphones, even the best ones, compared to our hearing apparatus, I never get tired of citing this example:

Sitting in an auditorium, and listening to a quiet passage of the orchestra, I can tune out the noise of the person sitting next to me rustling her candy wrapper. If I were listening to a recording of this event with a microphone placed where my ear is, I would be royally annoyed by the disturbance.
The brain can analyze sound waves delivered from the ear's sophisticated pathways, and filter out unwanted noise. The relatively primitive rendering of reality by a microphone does not make this possible.

To make such a test formally would I suspect be quite complex and challenging. It would have to be planned and executed very carefully at every stage. I notice you say "If I were listening" and "I would", implying you have never actually constructed such a test, let alone carefully sifted the results.  You just seem to assume that if you did, you would get a certain result. In addition, for the test to be more generally valid, it would have to include many subjects, not just yourself.

 If you have indeed conducted such tests formally and with proper rigour I'd be very interested in exactly how you went about it.

As well, I see a basic psychological hurdle with such a test. If people are listening to a live concert and someone makes continuous disturbing  noises in  quiet sections, what do affected listeners do? They often say "shhh". And if the person doesnt take the hint, they say "shhh" again. They can turn around, and glare  at the person. Then if the person still doesnt comply, action may need to be taken by the staff of the venue to formally warn the person or even remove them from the venue.

Whereas when we are listening to a recording of a concert we as a listener have no such control as the event has already happened. We are impotent to do anything about it. We can have no reasonable confidence that the noise will stop. Yes it would be frustrating and I have heard such recordings myself. Far more frustrating than the live situation where at least there's the possibility we can stop the  person from making the annoying noises...

Added to that is the bias of expectation. We are used to listening to professionally made recordings of live concerts where the microphones have been placed to minimise audience noise (except perhaps when the piece ends and carefully placed audience mics are skillfully faded up). That expectation alone could be hard to completely eliminate when listening to a recording made from a microphone placement position that no professional recordist would seriously consider. 

Just because we passionately believe something to be true doesnt make it true. Presumption  is the bane of science and common sense, and far from advancing our knowledge only keeps us in ignorance, I'd suggest.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 14, 2017, 02:36:23 am
If you have indeed conducted such tests formally and with proper rigour I'd be very interested in exactly how you went about it.
No I haven't and I don't think I need to, because a similar phenomenon, coughing on recordings, is proof enough for me that it's quite hard to ignore that on a recording, and much easier in a concert hall. Adding interactions with the culprit (glaring or worse) in a live context muddles the picture.

Which leaves me with the question, because I am losing track of what you are trying to communicate in all these lengthy posts of yours: Is there or isn't there an accurate microphone you can buy?
Title: Re: The Myth of the Accurate Microphone
Post by: sonicdogg on November 14, 2017, 01:08:44 pm
Interesting. Not everyone is able to 'tune out' the offending noisemaker in a live performance setting. I believe it is very much a brain function and at some point a choice by the individual. An example would be when , as a mix engineer, listening 'critically' at certain points of a multi-tracked session and trying to achieve balance, I can 'hear' all the parts but at the same time I am able, by choice, to tune out parts that I'm not engaged with at that moment in time. It doesn't mean they don't exist or are not prevalent, I just choose to ignore them.
 
There isn't a mic that can ignore content as far as I know.
 
Man I love reading this discussion!
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 14, 2017, 03:23:44 pm
Quote from: klaus
...Is there or isn't there an accurate microphone you can buy?

 Accurate for which purpose? Accurate within which limits?

It's like asking "Is human hearing accurate or isnt it?"
Same reply.




Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 15, 2017, 12:47:48 pm
Add the fact that everyone's hearing is and measures differently. Finding/setting a baseline is impossible because everyone has a differing baseline.

One man's Neumann is another man's B+K. I would love to see more research and development into this field but ever since the record biz broke the financial incentives have dried up. The current market share is reduced to clones and reproductions of older existing designs. It's MJ doing the moonwalk.

There are new materials to test and new designs to try out. Further down the road they may get the attention they need but at this point recordists are very comfortable with the choices they now have. That's another incentive that is missing.

The search for the mythical accurate microphone will just have to wait a few more decades. I expect the breakthroughs to come from the science and aerospace community, not the remnents of the recording industry.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 15, 2017, 10:28:48 pm
 When someone says that the response of even today's highest fidelity mics is "rough as hell" or that today's mics are "primitive" I ask:

1. Compared to what?
2. What evidence do you have for those claims?
3. How  did (or would) you go about testing those claims?

Tim
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 15, 2017, 11:37:34 pm
I did not write the "rough" part. But what I wrote about mics being rather primitive simulations of how we pick up sound, I stand by that. Our ears are sophisticated organs with an ability to discern and process highly complex signals of varying intensity and frequencies with incredibly high resolution, without smear, and three-dimensionally.

Given the choice, wouldn't we all prefer to hear the original source and not the miked copy?

That is not to say that mics are useless. They make up for some of their deficiencies with euphony: enhance or suppress aspects of the original sound, then sprinkle fairy dust over it (ELA M251, U47, etc. etc.)
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 16, 2017, 04:15:33 am
I did not write the "rough" part.

Quite. The "rough" comment was written on another audio forum, coincidentally by a repairer and servicer of microphones.

Quote from: klaus
But what I wrote about mics being rather primitive simulations of how we pick up sound, I stand by that. Our ears are sophisticated organs with an ability to discern and process highly complex signals of varying intensity and frequencies with incredibly high resolution, without smear, and three-dimensionally.

 Yes F. Alton Everest (1989) referred to hearing as "that marvellous sense" and went into detail as to its amazing complexity and ability, while also mentioning some of its limitations.

But as alluded to earlier, a mic is in a way just the equivalent to the mechanical parts of the  human ear: eardrum, hammer, anvil, stirrup, cochlea perhaps. Just like those human parts, a microphone doesnt pretend to  "discern" or "process" sound. It doesnt need to.  We the human listener do that mental interpreting when the signals from the ears reach our even more amazing brains.

Quote from: klaus
Given the choice, wouldn't we all prefer to hear the original source and not the miked copy?

Of course, not to mention actually being there at the live performance and seeing it all before our eyes. I'm greatly looking forward  to being at this year's live Messiah performance with soloists, combined choir and orchestra at our local university's fine  auditorium. Nothing like it.

But  again, where is the evidence that the reproduction from top mics - even from some  cheaper mics- is "relatively primitive"? I welcome it.
Title: Re: The Myth of the Accurate Microphone
Post by: jaykadis on November 16, 2017, 11:05:44 am
The human auditory system is far from perfect, but in fact that does not matter because what we perceive is interpreted by the brain into "hearing" incorporating the system's imperfections. The "accurate" microphone's job is simply to present to the auditory system a minimally altered representation of what an ear would have heard had it been in the place of the microphone. Microphones that create a distinctly imperfect representation are sometimes preferred for musical purposes while those that come closer to transducing the air pressure and velocity changes at the point of measurement into electrical signals would be considered to be more "accurate". Both approaches have their uses.


I am still waiting for a true digital microphone that can convert bulk molecular motions into an electrical signal.
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 16, 2017, 12:47:08 pm
Any digital based microphone design is limited by the front end that does the electrical conversion of sound pressure waves into an electrical signal. The digitizing comes after, not before the transducer.

Once encoded into an electrical signal, whether analog or digital the problems begin, not end. Then the rest of the system gets to do its destructive influence and removal of any reality that was originally preserved. Speakers are the worst offenders, none of them can approach the THD specs of a well designed microphone. Stick 5~10% THD on top of a low THD signal and it's a wonder we can discern any quality left at all.

In the end, electrical based audio reproduction sucks in it's ability to preserve the "moment". Until something else comes along, it's all we have right now besides the live experience.
Title: Re: The Myth of the Accurate Microphone
Post by: jaykadis on November 16, 2017, 02:15:21 pm
I envision a transducer that quantizes the air movement and force exerted at the molecular level, integrating the individual contributions in the device itself. Materials like graphene might make such a transducer possible, for instance. Thus the digitization becomes part of the transduction itself rather than a subsequent measurement. Clearly, this does not currently exist.

No argument about loudspeakers - they suck no matter how much money you throw at them.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 17, 2017, 05:30:17 am
The human auditory system is far from perfect, but in fact that does not matter because what we perceive is interpreted by the brain into "hearing" incorporating the system's imperfections. The "accurate" microphone's job is simply to present to the auditory system a minimally altered representation of what an ear would have heard had it been in the place of the microphone.

Not that I'm aware of. Mics normally output relatively flat. The human ear's response is not flat. It  has a special response a la the Fletcher Munson curves.  If mics responsed like the ear they would have a pronounced wide band peak centred  around 3 kHz and would sound overly midrange to us. But to take account of this fact, there are "weighting curves" incorporated in sound level meters which approximate how humans perceive sound levels and can be more realistic in some measurement situations.

Mics dont take the place of the ear. 




Title: Re: The Myth of the Accurate Microphone
Post by: jaykadis on November 17, 2017, 11:52:10 am
You misunderstand. The "accurate" microphone's job is to present to the ear what it would have received as input if it had been where the microphone was placed.

Unfortunately we also need a loudspeaker to deliver that stimulus to the ear so we're screwed regardless of how good the microphone gets at its job.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on November 17, 2017, 12:20:01 pm
My life got a lot easier (and my recordings got a lot better) when I ditched any illusion of (or aspiration for) "accuracy," and began to just listen and choose the subjectively best option.

The entire goal of recording is good sound. I am confident in my ability to use discretion, experience, and judgment to make that determination. I don't need any number or specification as a cosigner.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 17, 2017, 12:22:29 pm
Amen!
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 17, 2017, 03:46:12 pm
You misunderstand. The "accurate" microphone's job is to present to the ear what it would have received as input if it had been where the microphone was placed.
Ah, that's what you meant by "place". Understand now.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 17, 2017, 04:45:54 pm
My life got a lot easier (and my recordings got a lot better) when I ditched any illusion of (or aspiration for) "accuracy," and began to just listen and choose the subjectively best option.

The entire goal of recording is good sound. I am confident in my ability to use discretion, experience, and judgment to make that determination. I don't need any number or specification as a cosigner.

Yes but how do I know that my subjective listening judgement is at least within ballpark?   These days we can easily put our judgement to the test  by presenting what we consider good sound - or improved sound - to our peers, or even the world.  What do 10 or 10,000  people's experienced ears think of my opinion  of good sound, good recording, good musical balance etc - specifically my audio sample file?

Then it's more than just the private, untestable claim: "I know what my ears tell me." The person  prepared to  submit their audio claims to public scrutiny gains immediate credibility, and useful feedback about their own listening judgements.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 17, 2017, 08:15:19 pm
Quote
Yes but how do I know that my subjective listening judgement is at least within ballpark?

In the old days, those aspiring to a career in recording engineering did not get their chance to put their hands on the faders until they were thoroughly educated in the finer points of good balance, good splices and good tea-making.

The next hurdle they faced was whether enough artists, producers, or labels would hire them, so they could actually make a living off discretionary listening.

The next step was, whether enough peers of these engineers would agree that theirs was a damn well-engineered record, deserving a Grammy® for their effort. 

Though the path to becoming a recording engineer has radically changed over the last 10-15 years, success in the profession can still be checked out by listening to recordings universally hailed as tops, then listening to enough of them, until it's going to be self-evident what's a well-recorded piece of music, regardless of the reverb fashion of the moment.

If you do not yet have the confidence to trust your opinion whether a recording is well-engineered, start your listening education. Here, more is really better!
And soon enough you will recognize that "Purple Rain" is a rather poorly engineered album, and "Talking Book" an excellent one, regardless of both of them selling Platinum a few times over, and deservedly somas far as the music goes.

Next, listen to your voice through a TLM103; then, if you can swing it, through a real ELA M251 or any other of the Big Five.

With these kind of experiences under your belt, you will have climbed another rung on the ladder towards recognizing sonic excellence.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 18, 2017, 04:38:29 am

...With these kind of experiences under your belt, you will have climbed another rung on the ladder towards recognizing sonic excellence.
My post was not about me but anybody. That's why I wrote: "The person  prepared to  submit their audio claims to public scrutiny gains immediate credibility..."

Of course it could apply equally to the audio claims of a company.

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 18, 2017, 05:16:11 am
This is what you wrote, and to which I responded:
Quote
Yes but how do I know that my subjective listening judgement is at least within ballpark?
.
But now you write:
Quote
My post was not about me but anybody

Referring to 'anybody' makes conversations rather imprecise and impersonal. So if this subject does not pertain to your own subjective listening, why not take a break, and let others chime in?
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on November 18, 2017, 11:56:59 am
Yes but how do I know that my subjective listening judgement is at least within ballpark?   These days we can easily put our judgement to the test  by presenting what we consider good sound - or improved sound - to our peers, or even the world.  What do 10 or 10,000  people's experienced ears think of my opinion  of good sound, good recording, good musical balance etc - specifically my audio sample file?

Then it's more than just the private, untestable claim: "I know what my ears tell me." The person  prepared to  submit their audio claims to public scrutiny gains immediate credibility, and useful feedback about their own listening judgements.

"Good sound" is not (for me) an objective that gets completed, but rather a lifelong pursuit of a feeling. I hope that each record I make is better (read: more emotionally-resonant) than the last, for the rest of my career. I doubt I will ever feel like that mission has been wholly and indisputably accomplished. In that sense, there is no "ballpark."

And much like there's no objective metric to determine the "best guitar player," I feel there's no objective metric (or set of metrics) that can meaningfully determine the "best (read: 'most accurate') microphone."

Because things which can be measured are almost always relatively unimportant in the context of work designed foremost to move someone emotionally.

For example: There are many people who can jump higher, run faster, have higher IQs, and have more symmetrical facial features than I. My wife may even know some of those people, but she loves me. Why? Emotion is profoundly illogical. Those objective metrics have a laughably-poor correlation to why my wife might've fallen in love with me. Broadly speaking, to contrive to explain an emotional response in terms of available objective metrics is folly. For one thing, it opens us up to the cognitive biases of anchoring/focalism, the availability heuristic, ambiguity effect and the base-rate fallacy, among others. Simply put: most of what moves us emotionally cannot be measured, and that puts us at risk of over-emphasizing things which can, when making judgments.

And so it is with microphones. If I listen to a recording of a great vocalist on a great U47 and instantly feel an emotional connection to the performance--more than the same performance into a microphone that measures quieter, flatter, more extended-- then which do I choose?

Do I choose the person with the higher IQ who runs faster? Or do I choose the partner with whom I've fallen in love?

Not everything that matters can be justified through empirical means. This is especially so in matters of emotion--and my goal with creating or capturing music is always to elicit within the listener an emotional response.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 18, 2017, 01:25:05 pm
Thank you for your brilliant thought. I have copied it into my opening post.
KH
Title: Re: The Myth of the Accurate Microphone
Post by: panman on November 18, 2017, 03:14:12 pm
Yes Brad, that really was brilliant and well written.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 19, 2017, 06:48:05 am

 ...If I listen to a recording of a great vocalist on a great U47 and instantly feel an emotional connection to the performance--more than the same performance into a microphone that measures quieter, flatter, more extended-- then which do I choose?

Sure, no argument. So why not share it with others? Post comparison files, level matched etc, same performance, and see what others think...

Again, after listening to both, some might prefer the U47 vocal, while others might prefer the one with closer fidelity, and yet others might not even notice a difference, or if they do, arent much bothered by it. Some might just be more interested in the performance, the words, the story of the song, perhaps the emotion in the singer's voice. For them that's the emotional engagement, and they are perhaps indifferent to the sonic issues.

But regardless of whether one file sounds better, worse or indifferent to various listeners, we can be pretty certain that the mic with more fidelity has... more fidelity. Or am I jumping to conclusions here?
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 19, 2017, 01:50:43 pm
Your thinking is not clear:
if you upload files (an iffy proposition in the first place, due to, among many other reasons, lack of control of the test conditions by third parties), so that people can judge which of two mics has "more fidelity", the test is meaningless because the test subjects could not hear the original sound source with their ears, to compare which of two mics has the truest (fidel) representation of the original.
No baseline comparator, no test.

What you COULD do, and this would be best done in a controlled acoustic, not sound file, environment: put up two mics, any two, and a statistically significant number of listeners will prefer one of these mics for that specific sound source.

You could then go further and enlarge the test to using the better of two mics on many different sound sources (each time eliminating the worse-sounding one) and you will find that the Big Five end up near or at the top as finalists.

Then you really know what mics most recordists are lusting for, and why. And "fidelity" defined here as most true to one's image of the original source's emotional content will be the winner.
Title: Re: The Myth of the Accurate Microphone
Post by: sonicdogg on November 19, 2017, 02:20:43 pm


Not everything that matters can be justified through empirical means. This is especially so in matters of emotion--and my goal with creating or capturing music is always to elicit within the listener an emotional response.


 This is my new mantra.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 19, 2017, 04:30:45 pm
Your thinking is not clear:

 "Emotional content" is not always easy to pin down, but the irony is, without a certain minimum level of fidelity (in the standard sense of the word) no emotional content will be conveyed. For example for words to be understood. Remove enough treble, and speech become a meaningless mumble. Remove enough of the lows and all your hear are meaningless "sss"s  "fff"s, "t"s etc. Same for musical notes. It becomes very constricted and lifeless. 

Fidelity  has to be "good enough". It doesnt always have to be great. Just good enough for the purpose at hand.  So our telephone system was designed for speech intelligibility. People could also sing into a telephone call to a friend, using, from the strict fidelity point of view, the dreadful sounding standard carbon button microphone and yet the full emotion of that singing could generally be conveyed to the person at the other end.

That's why a term like "emotional content" in the context of comparing otherwise pretty high fidelity mics is I think not very useful. If "emotional content " can be conveyed  well enough over very limited fidelity telephone lines then it brings into question the association of that term with certain  mics. Beyond a certain point, certainly more  fidelity to the live voice will increase, but the "emotional content" has already been conveyed well enough with the much lower fidelity. How can that be?

An ear is just an ear. A mic is just a mic. Both are essentially  transducers.

But "emotion" is a quality of  mind. It is of a far different order.

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 19, 2017, 06:13:50 pm
You did not address my specific criticism of your unclear thinking, namely that, without direct and "live" comparator, no fidelity test as you envision is possible.

Then you picked words out of my concluding sentence that garbled my message.
I wrote:

Quote
"fidelity" defined here as most true to one's image of the original source's emotional content will be the winner.

One's IMAGE or memory of the original source's emotional content is the keyword here.
If you don't give the listener the original sound source when comparing a mic, the listener's image or memory of the (absent) original will be the next best source for evaluating a mic.

It's self-evident that a mic which lacks the ability to transmit bare essentials of sound transmission will not be chosen.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 19, 2017, 09:09:21 pm

...It's self-evident that a mic which lacks the ability to transmit bare essentials of sound transmission will not be chosen.

What are these bare essentials of sound transmission?
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on November 19, 2017, 10:15:21 pm
Sure, no argument. So why not share it with others? Post comparison files, level matched etc, same performance, and see what others think...

Should the requisite amount of "time off in my schedule" and the requisite amount of "inclination to further a discussion in an internet forum" ever coincide sufficiently to merit setting up such a properly-controlled experiment, I promise to share the results with you.

I know this answer is unlikely to satisfy at the present moment. I regret this. I do wish you the best of luck in your search for the perfect microphone!
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 20, 2017, 12:55:40 am
Should the requisite amount of "time off in my schedule" and the requisite amount of "inclination to further a discussion in an internet forum" ever coincide sufficiently to merit setting up such a properly-controlled experiment, I promise to share the results with you.

It was hardly a suggestion to do a properly controlled experiment. Just to put some vocal files out there, with  attention to basic things  like level matching, attention to proximity effect, vocalist on axis etc.  Nowhere near a "properly controlled experiment". Please  re-read what I actually wrote.

Quote from: soapfoot
I do wish you the best of luck in your search for the perfect microphone!

No need to. From what I have read of them, I would most happily use any of the listed "big five" mics on for example vocal recording, but lots of other duties as well. So long as they were in good condition, valve not overly noisy etc.
I wonder if you really know, Brad, where I am coming from here. Maybe with a little more time and patience we could come to a common understanding on this.

All the best,
Tim
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 20, 2017, 11:27:11 am
If that perfect microphone is ever developed, it will also require a perfect speaker to hear it.

We are closer to perfect microphones than we are to perfect  speakers.

Perhaps an implant will allow us to skip the speaker/hearing stage and feed the signal directly to the brain like Cmdr. Data or Rush Limbough?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 21, 2017, 09:04:30 am
We are closer to perfect microphones than we are to perfect  speakers.

A lot closer I suspect, and have been for maybe 70 years or more.

What I dont understand in this thread at least is:

1. the ridiculing of accuracy on the one hand...

but then

2.   the praising of mics like the great U47 which from its makers' own words was designed primarily to be accurate. (I can supply the relevent Neumann quotes)

One or the other yes, but, not both. There seems amongst some people almost a fundamental disconnect.  I'm still trying to work out the explanation.
Title: Re: The Myth of the Accurate Microphone
Post by: kludge on November 21, 2017, 09:21:43 am
Well, we can distinguish because microphones that were _designed_ to be accurate, and those that were designed to be deliberately inaccurate.  This creates the interesting category of microphones like the U47 that were designed to be as accurate as possible when they were originally made, but which people like today because of their inaccuracies.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 21, 2017, 10:17:00 am
Yes but even today, their inaccuracies are relatively minor, I'd suggest.

Unfortunately confirmation bias can be very strong in some people. I believe the only way to sort this out is true blind listening tests where people have no idea which mic they are listening to.
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 21, 2017, 11:12:54 am
Blind listening "tests" are not so blind when you are required to use a less accurate speaker than the mic is under test. Then add more errors from the power amps, converters or preamps, cabling, room, etc.

It's like trying to push down a floating ping-pong ball with your thumb.

"Two steps forward and one step back" ~Johnny Winter
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 21, 2017, 04:19:09 pm
Exactly. Michael O first raised the subject in this thread. The accuracy weak link/bottleneck is the playback, with the distortions of speakers and  rooms first by a large margin over amps, converters and cables etc. Not just in a blind listening test but any playback.

So again, why the focus on the much smaller accuracy weaknesses of the mic, and then paying big money for a barely "character" mic whose effect is swallowed up in the far more "characterful" playback.

To minimise the playback losses in blind listening to one mic, we can  listen on good quality headphones, which also removes the contribution of the room. For critical listening tasks many people do use quality headphones.
 
But on one point I differ, Jim. The defects of the playback, adding its own distortions, do not make the blind listening test less blind. They make it more blind, or deaf, by blurring away subtle differences. Another reason why many listeners dont want to subject themselves to blind listening tests when knowing what piece of gear being listening to results in so much more confident opinions. ;)

Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on November 21, 2017, 11:20:25 pm
Let's clear something up here--

I don't like the U47/U67/U87/etc "because of their inaccuracies."

I like them because they sound good.

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 22, 2017, 04:08:55 pm
What I dont understand in this thread at least is:

1. the ridiculing of accuracy on the one hand...

but then:

2.   the praising of mics like the great U47 (...)

One or the other yes, but, not both. There seems amongst some people almost a fundamental disconnect.  I'm still trying to work out the explanation.

MY explanation since the start of this conversation had been:
Selling a mic as "accurate", whether doing so fifty years ago or today, is misleading. There are no accurate mics as long as there is no agreement which of them is most accurately representing the sound source as we hear it with our ears.

At best, the inaccurate but euphemistic additions and subtractions that mics like any of the Big Five deliver, will deliver to the listener the perceived musicality of, and emotional connection to the live performance.

Again, taking subjective perception out of the discussion is fallacy, as long as only subjective perception tells us in the end what truly matters in a mic.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 23, 2017, 07:37:17 am
MY explanation since the start of this conversation had been:
Selling a mic as "accurate", whether doing so fifty years ago or today, is misleading. There are no accurate mics as long as there is no agreement which of them is most accurately representing the sound source as we hear it with our ears.

As I understand it, audio equipment testing is based on two complementary approaches which are meant to be the two sides of the one coin:

1. formal  measurement
2. subjective listening

Quote from: klaus
At best, the inaccurate but euphemistic additions and subtractions that mics like any of the Big Five deliver, will deliver to the listener the perceived musicality of, and emotional connection to the live performance.


Euphemistic distortions definitely have a place in live amplified performance and recordings and can be perfectly acceptable artistically, although not in every music genre and definitely not to everyone's taste. But if fidelity/accuracy is the criterion - as you appeared to make it the criterion in this thread - euphonic distortions reduce fidelity/accuracy.

Quote from: klaus
Again, taking subjective perception out of the discussion is fallacy...

As far as I know nobody is taking subjective perception out of the discussion. Far from it.
But again I'd suggest listening is only one side of the normal evaluation coin, the other being formal measurement, as mentioned above.

Quote from: klaus
.. only subjective perception tells us in the end what truly matters in a mic.

Are you taking objective measurement of equipment performance, including mics, out of the discussion?

Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on November 23, 2017, 12:14:41 pm
Objective measurements with current audio test kits are also far from mature or complete. Yes, an Audio Precision is a wonderful tool, I have one.

It will show errors, at least some of them. It will not qualify quality of sound. 
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 23, 2017, 06:21:17 pm
 I agreed how important is listening, supported by objective audio measurement.  The limits of human hearing can inform our discussions of equipment and testing. For example if under even ideal conditions nobody can hear distortion  100db below the fundamental tone, how important are audio gear distortions 110db down?
 
When the equipment under test, the test equipment and procedure must be unbelieveably accurate while human hearing is not required to meet anything like that stringent standard, that sounds to me like a double standard.

I remember encountering this repeatedly on a forum discussing analog tape gear. The argument was that to compete with analog recorders, digital recorders must have "perfect" reproduction, while with analog recorders, "who cares about a bit of noise, distortion and wow and flutter?"

Cognitive bias is a long standing issue, and not just in the audio world...

https://en.wikipedia.org/wiki/Confirmation_bias

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on November 24, 2017, 04:31:45 am
I agreed how important is listening, supported by objective audio measurement.
If something sounds good, it is good. I don't need to construct a measurement aura around it.

And if you want to bring cognitive bias into the conversation, then spell out how in your opinion it affects sound impressions, and how to avoid it.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on November 24, 2017, 08:53:13 am

... if you want to bring cognitive bias into the conversation, then spell out how in your opinion it affects sound impressions, and how to avoid it.

I  already introduced it into the conversation. Earlier in this thread I wrote:

Quote from: Timtape
Unfortunately confirmation bias can be very strong in some people. I believe the only way to sort this out is true blind listening tests where people have no idea which mic they are listening to.

I also cited the Wiki page on confirmation bias in general:

https://en.wikipedia.org/wiki/Confirmation_bias

Here's a Wiki page specifically on audio equipment testing:

https://en.wikipedia.org/wiki/Audio_equipment_testing

These are just two examples. Much other material out there.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 02, 2017, 09:06:09 am
I'm glad you brought up confirmation bias, because it's salient here. If, before auditioning a microphone, I examine some data to find that the microphone advertises


That information sets me up to believe, before I've even heard it, that the mic will perform well. Why do you think so many mic manufacturers include such figures and graphs in their marketing literature? But these data are not, in fact, especially reliable predictors of a mic's subjective performance in my experience/opinion.

I've always related to H.H. Scott's logic: "If it measures bad and sounds good, it's good. If it measures good and sounds bad, you've measured the wrong thing."

It's a mistake to assume that the "objective audio measurements" we're undertaking aren necessarily a) the most significant predictors of good sound as perceived by humans, and b) made under the most germane conditions (particularly when they're made by the manufacturers themselves).

Numbers are easy to understand. Metacognition is hard, thorny, and a moving target. So we tend to be easily seduced by the former, and gloss over the latter. How we perceive sound, though, is as or more important to audio than the bare physics of the sound. And when we do attempt to address perception in some way (such as with A-weighting of noise measurements), it tends to be crude.

But there's clearly much more to the story. There are several microphones which roll off at 30 cycles (or 15k cycles) that have been widely embraced by professionals, and plenty which measure ruler-flat, DC-to-light (metaphorically) that have fallen by the wayside. To explain this as some sort of mass delusion (or mass preference for distortion and narrow bandwidth) would be rhetorically lazy, so I've learned to embrace this metacognitive inconsistency as part of the mystery of audio. It's one reminder of just how far we have to go when it comes to understanding human perception of (and preference for) one sound versus another.

I'll leave you with one thought: I contend that there can be no such thing as true objectivity in a topic as broad as microphone performance. Because even the most rigorous methodology begins with a human's opinion about what's important; what's worth measuring, and under what conditions it should be measured. And even brilliant scholars can have blind spots.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 02, 2017, 12:38:56 pm
If, before auditioning a microphone, I examine some data to find that the microphone advertises
  • an extended frequency response that doesn't deviate more than 0.5 dB
That information sets me up to believe, before I've even heard it, that the mic will perform well.
Come again? Neumann, a leader in high quality condenser mics, usually specifies ±2dB across the transmission range, and I am unaware of anyone doing any better. The bulk of that tolerance, by the way, can be attributed to capsule variations, while Neumann's mic amps, downstream from the capsule, are typically within ±0.5dB.[/list]
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 02, 2017, 01:59:16 pm
I take your point
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 02, 2017, 10:18:02 pm
Brad, yours is a long post. I choose to deal with it one point at a time, the first being:

I'm glad you brought up confirmation bias, because it's salient here. If, before auditioning a microphone, I examine some data to find that the microphone advertises

  • an extended frequency response that doesn't deviate more than 0.5 dB
  • very low THD+N figures

That information sets me up to believe, before I've even heard it, that the mic will perform well...

OK.  Same solution. Blind listening where nobody  knows what mic they are listening to, and therefore what  '"specs" they are listening to, whether claimed or actual.

If we really want to  circumvent confirmation bias...we can.






Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 03, 2017, 10:49:49 am
Brad, yours is a long post. I choose to deal with it one point at a time, the first being:

OK.  Same solution. Blind listening where nobody  knows what mic they are listening to, and therefore what  '"specs" they are listening to, whether claimed or actual.

If we really want to  circumvent confirmation bias...we can.

Blind listening is great.

However, what's near-impossible is blind working. And I'm continually amazed at how often the thing that wins the "shootout" doesn't win in context; isn't selected when actual music is being made and recorded.

It took me some years to learn this for myself-- but now I seldom-ever do "shootouts" anymore, blind or sighted. I've just found that, for me, they're not all that predictive of what I'll find useful when doing actual work
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 03, 2017, 12:02:42 pm
If we really want to  circumvent confirmation bias...we can.

Not really at this point of audio equipment development. Everything else in the system also imparts its own sonic signature as well. That skews the tests every time.

When you get to the point when even a power cable changes the sonic picture you are also evaluating the "rest of the story".
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 03, 2017, 01:29:25 pm
Jim Williams raises a relevant point. We could not begin to explore the original premise (the possibility for an accurate mic) unless we identify and factor each active and passive component's contribution to the sound arriving back at our ears.

What is left, then, is a rather clumsy approximation to "accurate": Which total chain sounds closest to what we liked in the original experience?

That brings us right back to my original skepticism: we cannot even begin to search for, let alone, identify, an accurate mic until we can extract and isolate the mic from the rest of the recording/reproduction chain.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 03, 2017, 04:17:09 pm
Blind listening is great.

However, what's near-impossible is blind working. And I'm continually amazed at how often the thing that wins the "shootout" doesn't win in context; isn't selected when actual music is being made and recorded.

Sure in a work situation, being blind to the gear we use can be very difficult.  But you mentioned the making and recording of music  changing which mic you choose. Can you give some practical examples?


Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 03, 2017, 04:23:43 pm
Quote from: Tim
If we really want to circumvent confirmation bias... we can.

Not really at this point of audio equipment development. Everything else in the system also imparts its own sonic signature as well. That skews the tests every time.

When you get to the point when even a power cable changes the sonic picture you are also evaluating the "rest of the story".

Again, confirmation bias is  a cognitive issue, not an  equipment issue.  Again, if you're not familiar with the concept, please read up on it in the relevent sources. Here's one: https://en.wikipedia.org/wiki/Confirmation_bias
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 03, 2017, 05:56:28 pm
Sure in a work situation, being blind to the gear we use can be very difficult.  But you mentioned the making and recording of music  changing which mic you choose. Can you give some practical examples?

Sure.

The humble Shure SM57 is popular on guitar amp. But even in that application, it's not always something I find exceptionally gorgeous in "solo." It's certainly not anything anyone would ever describe as "accurate" (whatever that could possibly mean). It's got weird resonant peaks in its frequency response, a presence peak, a roll-off beginning around 200 cycles, its off-axis coloration is pronounced and not-too-helpful, always, etc.

However, in the context of a distorted electric guitar in a production I often prefer a good 57 to more expensive microphones which sound subjectively preferable in "solo", and which are objectively better in almost every commonly-measured way. It's a very popular microphone in this application, so either 2-3 generations of professionals are "easily led," or there's something about it that just works exceptionally well in that application, leading to the consensus.

Or for another example-- an RCA 44BX in good condition doesn't have a bandwidth extending much beyond 15k cycles (and is far-from-flat at least an octave below that). But on a trumpet, I prefer it to most other microphones, generally speaking-- even to expensive vintage German and Austrian condensers costing 5-10x more, and certainly more than modern offerings from the likes of DPA, etc which measure far better in every way.

My personal preferences are not overly meaningful. But to the extent that there's some degree of consensus among working professionals, that also constitutes data-- data that's every bit as meaningful as anything an Audio Precision Analyzer could measure.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 03, 2017, 09:13:57 pm

 ...in the context of a distorted electric guitar in a production I often prefer a good 57 to more expensive microphones which sound subjectively preferable in "solo",

As we know, compared to condensers, dynamic mics are almost immune to distorting under high SPLs. If the condenser mic overloads badly, it will probably sound horrible, adding unpleasant distortions that aren't coming from the amp cab.
So in this context, the SM57 which isnt overloading under the high SPL, is actually truer to the sound of the amp cab. It's more accurate to the source.

Re: the RCA 44BX on a trumpet. The trumpet  can have incredibly piercing highs especially when played full force and - unlike the player - we're standing in front of it! It's natural to sometimes want to tame some of those highs in a recording as it can sound more pleasing. Using a mic with  somewhat rolled off highs can be one way to achieve  that.
In this case we're talking about deliberate (but often perfectly valid) inaccuracy to the source.

Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 03, 2017, 10:10:44 pm
1) I know the difference between an overloading microphone and a subjective personal preference.

2) I've never had a problem with frequencies above 15k on trumpet on any microphone. If anything is problematic, it's usually a strident (upper) midrange (well within the capabilities of a 44BX).

I disagree about "deliberate inaccuracy."

I select microphones, typically, that sound most to me like the source sounds in the room. I maintain that there's a decidedly imperfect correlation between that characteristic and a microphone's measurable parameters. Otherwise there would exist such a thing as the "perfect microphone," and I've yet to encounter it.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 04, 2017, 04:35:15 am

Quote from: soapfoot
I select microphones, typically, that sound most to me like the source sounds in the room. I maintain that there's a decidedly imperfect correlation between that characteristic and a microphone's measurable parameters. Otherwise there would exist such a thing as the "perfect microphone," and I've yet to encounter it.

How a source "sounds in a room" can vary enormously, not least on the characteristics of that room,  the placement of the source in the room, and our placement in the room, in relation to the source. There is no one sound - unless maybe the room is an anechoic chamber. So which sound is preferable? It's a choice of course.

Placement of the mic in relation to the source in the room is equally important, often far more important that the mic's spectral characteristics. Mic placement makes a huge difference, and again is a choice. 

Related to this, and recalling Klaus's candy wrapper example, I've been surprised that this subject hasn't been referred to in the thread:

https://en.wikipedia.org/wiki/Dummy_head_recording

http://www.neumann.com/?lang=en&id=current_microphones&cid=ku100_description
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 04, 2017, 11:36:03 am
Thr trumpet has a large amount of upper harmonics present, all the way to 50k hz.

Seems no one ever complains about the sound of a trumpet until we stick our less than accurate stuff in front of it.

Most microphones cannot deal with all those upper harmonics so they either distort them or in the case of a ribbon mic, low pass them.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 04, 2017, 01:41:26 pm

https://en.wikipedia.org/wiki/Dummy_head_recording

http://www.neumann.com/?lang=en&id=current_microphones&cid=ku100_description

Your reference to dummy head recording is problematic:
You need to listen over headphones to re-create the binaural experience, and even with headphones, the results are, musically speaking, poor, despite the three-dimensional impression they give.

I never figured out why dummy head recordings lack musical warmth. Could be the plastic material of the simulated ear canals, could be the size and placement of the membranes...

An interesting direction for more a ergonomic type of recording that was never optimized to overcome its shortcomings. Probably too few takers to invest a lot of energy and money to try to perfect it.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 04, 2017, 06:39:16 pm

Thr trumpet has a large amount of upper harmonics present, all the way to 50k hz. Seems no one ever complains about the sound of a trumpet until we stick our less than accurate stuff in front of it.

Forget microphones and gear  for a moment, and consider a more commonplace example. Some peoples' sibilants are  loud compared to their consonants and can annoy many people listening. A friend of my late mother used to speak her sibilants VERY loudly. My Uncle found it very uncomfortable and  humourously nicknamed her "sss".

In the old days, sibilants, cymbals etc caused major problems for disc cutting and for other low fidelity media, causing often massive audible distortion.  The recording gear, including mics steadily got much better and can now handle pretty much anything.

But an annoying sound is still an annoying sound! So no surprise recordings are often produced with EQ, de essing and other artificial manipulation of otherwise natural sounds not just because the gear might struggle to capture or reproduce it - though that can  be true with cheaper gear - but also because it is a more pleasant sounding balance to most listeners. That's why strict fidelity in recordings, while a good general rule, is not always desirable for the listener, just as a very sibilant person is not always appreciated in real life. 

Most microphones cannot deal with all those upper harmonics so they either distort them or in the case of a ribbon mic, low pass them.

We cannot hear ultrasonics. That is what the term means.  The only reason we could know trumpets have harmonics to 50kHz is because a specialised mic capable of that band faithfully captured them! And a specialised analyzer plotted them in a form we can see but not hear.  So if we cant hear them, why capture them? In practice there are very good reasons not to capture them. But that's another discussion perhaps.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 04, 2017, 07:19:49 pm
Your reference to dummy head recording is problematic:

Your problem then is with  great microphone companies like Neumann and Bruel and Kjaer. Good luck with that...
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 04, 2017, 07:37:20 pm
Your response, punctuated with "good luck with that" is not helpful. Neither is your dismissive tone counter-arguing opinions that differ from yours.

I do not have a "problem" with "great microphone companies" but in my post I brought up reasons why, in my opinion, and based on my personal experience, dummy head recordings have never caught on with the public, despite their promise of three-dimensional reproduction.

Your arguments why you think dummy head recording is significant, are welcome, especially if they are derived from personal experience. But snippy retorts are not the way to do this, at least not on my forum.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 05, 2017, 09:46:41 am
My apologies if my words were unhelpful.

It's been an interesting time discussing microphones with a few of you.
Title: Re: The Myth of the Accurate Microphone
Post by: mbrebes on December 09, 2017, 11:45:32 am
There are few problems with the theoretical "accurate" microphone that have not been discussed but have been alluded to by some of the comments throughout this thread:

How do we measure the accuracy of a microphone?

1. We put the microphone in front of a speaker system, with all its linear and distortion errors (brought out by Jim Williams) that has been normalized for flat response using a test microphone that has been tested to be within a certain accuracy (yet another problem). We then measure the microphone with this "normalized" system to get a frequency response at one point directly in front of the microphone, with a given distance (already discussed), and at a given level.

2.  Off-axis measurements seem to be rudimentary at best, with usually two or three frequencies displayed.  In my experience with measurement microphones, I have found that they all have high end roll-off the farther off-axis you go. Microphones of the side-address variety might show some very interesting responses as they are measured close to the body of the mic.

3. I have never seen a measurement of the linearity of loudness in microphones or the loudness versus frequency.  I think we would find some very enlightening information from these tests.

My point is that the more we investigate the "accuracy" of a microphone the more we will find that there is no such thing, and no real way to measure it. 

We are left with using microphones that we like, for whatever reason, for specific situations.  Yes, my reality is not the same as the next person, but that's all we have.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 09, 2017, 12:49:20 pm
We are left with using microphones that we like, for whatever reason, for specific situations.  Yes, my reality is not the same as the next person, but that's all we have.

And, aside of insecurities that some have about trusting their ears and musical judgement: what's really wrong with that?

It's the sensuality of the experience that makes it so much fun driving a car whose engine sits over the (rear) drive wheels and plants the car, for immediate and direct input/feedback to the driver. 'Objective' horsepower or torque data cannot not show that: you may be fooled by a front engine/rear drive car's superior power stats but ultimately inferior "seat of the pants" experience.

I understand that many people in the audio world do not trust what they hear, but I believe it's a cop-out to then try to defer to measurement crutches, to "verify" what they hear, to avoid getting egg on their faces for sticking out with an opinion possibly not shared by others.

I have seen this so often at demos of high-end audio components in rented suites at trade shows. Most of these systems are not particularly good, but you will rarely hear critical comments, especially if the system demonstrated costs a lot of money.

Listening education these days is woefully undervalued and underutilized. Yet, trust in one's hearing increases with deliberate and continued training efforts.
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 09, 2017, 06:23:53 pm
I have seen this so often at demos of high-end audio components in rented suites at trade shows. Most of these systems are not particularly good, but you will rarely hear critical comments, especially if the system demonstrated costs  a lot of money.

I've been thrown out of several of those demo rooms when they didn't like my comments. Besides their ego hit they don't want the other lemmings asking questions either.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 09, 2017, 11:14:36 pm
There are few problems with the theoretical "accurate" microphone that have not been discussed but have been alluded to by some of the comments throughout this thread:

How do we measure the accuracy of a microphone?

1. We put the microphone in front of a speaker system, with all its linear and distortion errors (brought out by Jim Williams) that has been normalized for flat response using a test microphone that has been tested to be within a certain accuracy (yet another problem). We then measure the microphone with this "normalized" system to get a frequency response at one point directly in front of the microphone, with a given distance (already discussed), and at a given level.

2.  Off-axis measurements seem to be rudimentary at best, with usually two or three frequencies displayed.  In my experience with measurement microphones, I have found that they all have high end roll-off the farther off-axis you go. Microphones of the side-address variety might show some very interesting responses as they are measured close to the body of the mic.

3. I have never seen a measurement of the linearity of loudness in microphones or the loudness versus frequency.  I think we would find some very enlightening information from these tests.

My point is that the more we investigate the "accuracy" of a microphone the more we will find that there is no such thing, and no real way to measure it. 

We are left with using microphones that we like, for whatever reason, for specific situations.  Yes, my reality is not the same as the next person, but that's all we have.

Hi Michael, I'm not sure how familiar you are with the calibration of measurement microphones according to international standards. It's a very technical area but you and other forum readers might care to read this  accessible Primer from Bruel and Kjaer:

https://www.bksv.com/doc/br0567.pdf

I dont claim to be an expert working in this field so I defer to people who are and will happily cite their articles.

Cheers
Tim
 
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 10, 2017, 01:28:15 am
I am actually more interested in YOUR take on these things than referrals to manufacturers' publications, not that that's not interesting reading in itself.

To keep with the experiential mission of this forum: do YOU use measurement microphones for your musical recording work? If so, how do you like their translation of the music?

If you don't use them, what can you contribute from your experience to the subject of "accurate" vs. the myth of "accurate"?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 11, 2017, 09:23:33 am

It's the sensuality of the experience that makes it so much fun driving a car whose engine sits over the (rear) drive wheels and plants the car, for immediate and direct input/feedback to the driver. 'Objective' horsepower or torque data cannot not show that: you may be fooled by a front engine/rear drive car's superior power stats but ultimately inferior "seat of the pants" experience.

With your exciting rear engined, rear wheel drive car, instead of a motor of 500bhp, lets reduce it to 5bhp and see if that makes no difference to the thrill of driving it. ;)

As with microphones, objective performance means nothing except when we havent got it any more. It's called taking it all for granted and then when we lose it, wondering why the playback sounds funny...or the car barely gets going...

Even today a U47 mic performs quite well because of its still respectable objective performance.
But like the car engine, try seriously derating its objective performance, and lets see if it still has "the magic"...
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 11, 2017, 11:41:20 am
The logic of your post escapes me. Are you saying that, once you sabotage a mic, it becomes obvious what its supposedly "objective" qualities were?

P.S.:
Quote
Even today a U47 mic performs quite well because of its still respectable objective performance.

How would you know the "objective" aspect of a mic's performance? You offer no proof for that claim. It might as well be a clever euphonic design, producing a sense of well-being and connectedness to the music in the listener, which is then assumed "objective".
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 11, 2017, 05:55:23 pm
... It might as well be a clever euphonic design, producing a sense of well-being and connectedness to the music in the listener, which is then assumed "objective".

Yes adding distortion  can increase listening enjoyment - I sometimes  love it. It also decreases fidelity to the source. Are we agreed on that?

But point taken. Equally someone might listen to a recording and assume they enjoy it more because of the "toob/transformer/analog tape" type distortion - only to be reliably informed that there was no such distortion added, or discover that their perceived enjoyment was due to  something else - or was just imagined.

As discussed earlier, we human beings can tend to believe what we want to believe. It can take quite an effort to avoid such convenient presumption. Perhaps we're never completely free of it. 

Do you agree? 
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 12, 2017, 11:08:30 am
For the average music consumer, the sound of the recordings are the least of their concerns.

That concern is reserved for folks like us, a distinct minority of listeners. The rest of the audience is quite happy with low fi bit reduced audio.

As much as we care about that stuff it is reflected in the complete absence of concern from the rest of the listeners.

It's important to keep that reality in mind less we get too caught up with our own opinions.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 14, 2017, 06:13:53 pm
You and I can take a mic, plug it into a suitable amp with high quality headphones,  say "check, 1,2,3" and listen to the result on the headphones. That has great value but it is not what we are talking about here.


How would you know the "objective" aspect of a mic's performance?

I'm not able to do this. Perhaps you arent able to do this. That doesnt mean it cannot be done.

We might have to  pay people to measure its objective performance to within National  Standards and tolerances, whether primary or secondary standards.

That is my understanding anyway.
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 15, 2017, 03:53:12 pm
When a human is involved as a tester the test becomes subjective, not objective.

That is why modern audio test equipement was invented. It won't test everything but everything it tests is objective.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 15, 2017, 11:43:36 pm
I'd like to nudge the discussion back to the original subject: accurate mics are a myth.

To start with, virtually all microphone products which emphasize claims of accuracy are not selling well, compared to other mics in the premium price class.

So what's the problem here? It's either that the product does not achieve the manufacturer's claim, and potential customers notice its shortcomings, or the claim itself is pointing in the wrong direction by appealing to a goal not perceived by a critical mass of engineers as either attainable or worthy.

Microphones are meant to transport sound waves that are ultimately meant for, and can only be interpreted by, human hearing. Few top-flight engineers, artists, and producers seem to appreciate a type of microphone that caters to a different goal.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 16, 2017, 11:16:30 pm
Responding to your post Klaus:

Earlier I suggested that in mere music recording, the strictest accuracy in a mic is unnecessary.

In addition, many vocal artists want a mic that "makes me sound better than I actually am".  What characteristics in a mic make a particular vocalist "sound better"? Will a wide range of  listeners, producers, engineers all agree on which mic makes which vocalist "sound better", let alone "best"? We're now in subjective territory.

Then as many who  make recordings for release to the public know, other effects such as EQ, reverb and compression have been regularly applied to the vocal, and other instruments for many decades. These days, much more detailed "microsurgery" can be made. What we have been  hearing on many recordings for decades is not simply the raw output of the mic(s). 

Then there's the issue of the playback equipment used, and the general listening environment, which varies hugely. Then the preferences of the listener.

But all this is a long way from the original topic concerning the accuracy of microphones... which I thought we were getting back to.



Title: Re: The Myth of the Accurate Microphone
Post by: Marik on December 25, 2017, 01:54:56 am
I'd like to nudge the discussion back to the original subject: accurate mics are a myth.

To start with, virtually all microphone products which emphasize claims of accuracy are not selling well, compared to other mics in the premium price class.

So what's the problem here? It's either that the product does not achieve the manufacturer's claim, and potential customers notice its shortcomings, or the claim itself is pointing in the wrong direction by appealing to a goal not perceived by a critical mass of engineers as either attainable or worthy.


Klaus,

First, earlier you mentioned that B&K/DPA are not popular--sure, they are not for everything and everyone, but there are uses with superb results--notably in classical music, Baroque Ensembles, orchestra recordings, piano, among others, i.e. where the least of color and max intelligibility between notes/different groups are of concern... For example, I have hard time of imagining putting mint original Elam251 on classical piano... In this respect, we can say that say, DPA, or Schoeps would be more accurate, which anyway, has rather relative meaning, to start with.

I don't have statistics on my hand, but I'd think they do not sell as much as some others just because they have uses in much smaller market, but of course, by no means it says that they are inferior.

Microphones are meant to transport sound waves that are ultimately meant for, and can only be interpreted by, human hearing.

I believe, the problem here is much more complex and a lot has to do with psychoacoustics. Ultimately, for us as listeners the idea of 'accuracy' in the end is how well the music source in real life (or our idea about it) translates into the recording. Here not the least plays obvious mismatch of translation of directionality of source, acoustics of the room, our hearing, and subsequent playback chain. I.e. mechanism of this translation is disturbed from the very beginning...

That is, our ears in real life in the room 'hear' the music source omni, with natural acoustics/reverberation of the room. When we need to translate music event of the given source through recording we put say, cardioid microphone, we place a singer into a booth, after that play back through the speakers (are they omni, cardioid, fig8, or what?) and then our 'omni' ears and our brain should answer main question--does it sound true to the source, or does it sound musical (mind you, in a completely different room)?

In a sense it reminds translation to a foreign language, say, Hamlet--take Wieland, Schlegel, and Flatter German translations of the monologue--all of them are completely different... but still Hamlet monologue. Is the translation accurate? After all any translation is just interpretation and the answer is if that interpretation finds our emotional response and if what we hear during the playback matches the image of 'ideal sound' in our brains...

BTW, aforementioned binaural heads did not get wider use exactly for that directivity mismatch. While they sound well in headphones they just did not translate through the speakers.

Best, Mark Fouxman
Samar Audio Design
www.samaraudiodesign.com
Omni8 Audio
www.omni8audio.com
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 25, 2017, 01:48:28 pm
Two notable labels using B+K mics are Pony Canyon Classics and MA Recordings.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 25, 2017, 04:46:13 pm
...And two notable audiophile labels that use(d), pardon my language, "subjective" mics on pianos: Chesky (SM69) and Windham Hill (U67). 

B&Ks/DPAs, in my opinion, are just another flavor that works well in some applications, and not so well in others. This proves to me my point again: there's no such thing as an accurate mic, only ones that, in a particular situation, translate musical intention well, or not so well.

Merry Christmas, and a healthy New Year, everyone, and thanks for keeping things lively around here!
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 26, 2017, 10:19:53 am
Again, a mic's "accuracy" or "fidelity"  relates to  how well its electrical output conforms to the sound pressure waves presented to it. National and International standards are based on this objective criterion. Here, tastes, preferences and opinions are irrelevent.

Interestingly Chesky has been making and marketing dummy head recordings using small Bruel & Kjaer mics:

"In 2011, Chesky Records incorporated High Resolution Technology in their label, and introduced binaural recordings. The Binaural+ masters are captured in high-resolution (24-bit/192kHz) sound using a binaural dummy head nicknamed "Lars". David Chesky collaborated with Princeton professor Edgar Y. Choueiri to begin producing binaural recordings. The purpose of the technology is to capture three-dimensional sound and imaging."

Ref: https://en.wikipedia.org/wiki/Chesky_Records
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on December 28, 2017, 08:59:44 am
Again, a mic's "accuracy" or "fidelity"  relates to  how well its electrical output conforms to the sound pressure waves presented to it.

But how would one measure "the sound pressure waves" for comparison except with a microphone?

If there's no other way, isn't any assertion of "accuracy" a textbook demonstration of the logical fallacy "petitio principii," also known as "begging the question?" (https://en.wikipedia.org/wiki/Begging_the_question)

A scholarly conversation does not look like this:

Person A: "How do you know that a microphone can give an accurate measure of the sound pressure?"

Person B: "Because I also measured the sound pressure with a microphone, and it was accurate."

That won't do.

The central question then becomes: what is your reference for "the sound pressure waves," and how was it obtained?

Because unless we have a reliable, precise, and agreed-upon method of measuring "the sound pressure waves" that does not rely on microphones (i.e. "the device under test,"), then any reference is arbitrary, and any comparison not-so-meaningful.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 28, 2017, 11:20:54 am
(Note from KH: Soapfoot deleted sections of his post after Timtape responded. I therefore removed comments of Timtape which referred to these sections.)

Your question about absolute sound pressure levels is an excellent one. As I understand it the basic answer is that we create the sound pressure waves via methods that are known and repeatable.

For a start, you could Google key words like "pistonphone" and "electrostatic actuator" as I did. That should get you into the general field. There's a particular standards article I came across last week. Will try and track it down tomorrow.
 
It's half past midnight over here so I need to hit the sack. To be continued.

Tim



Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on December 28, 2017, 11:32:03 am
I consider a standard microphone a "snapshot" type device. It only captures from one perspective and ignores the surround location information.

An omni pattern will pick up air motion from all angles but does not provide any directional cues. The human ear can do that with only one working ear. That is why when you bury one ear in a pillow you can still determine the sound's directional source.

There were/are some directional sensing microphone designs, one was the "henry" from the 1980's. A recording from that mic provided all the 360 degree directional cues in a standard stereo playback format. It even worked well on cassettes. I recall studying those waveforms for the hidden directional cues but could not seperate them.

One of the more interesting sound samples was an electric shaver run from the top of the head downward. It showed as a mono source but one could easily hear the sound moving from the top of the head centered downwards, just like a real shaver would.

Part of that mic's design was the inclusion of location reference tones as produced by the human ear. Although inaudible, they were part of the mic's technology. I'm not sure what ever happened to those designs but they were very impressive.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 29, 2017, 02:51:33 am
An omni pattern will pick up air motion from all angles but does not provide any directional cues. The human ear can do that with only one working ear. That is why when you bury one ear in a pillow you can still determine the sound's directional source.

Yes some facility  remains but the directional sensing enabled by the pinna (outer ear) seems to be limited mostly to the vertical plane (above, level, below the head). It seems the brain senses partial frequency cancellations varying between about 6kHz to 10kHz.  So while undoubtedly useful it is  inferior on its own compared to the full 3D location sensing abilities of two fully working ears. (See F. Alton Everest, 1989, pp 19 and 20.)

Interesting that dummy head recording microphones include the outer ears to presumably capture the location cues in the vertical plane, as well as the left/right.



Title: Re: The Myth of the Accurate Microphone
Post by: klaus on December 29, 2017, 02:44:26 pm
(...) but the directional sensing enabled by the pinna (outer ear) seems to be limited mostly to the vertical plane (above, level, below the head).

Have you tested and confirmed the claim that directional sensing of an individual ear is mostly limited to the vertical plain?

How about trying this:

Rub your thumb against your index or middle finger, move it in the horizontal plane from front to rear, back to front: can you follow the rustling sound?
Do you get any less directional sense from rustling horizontally than making the same move in the vertical plane? I certainly don't. I hear them both equally distinct.

(Not that any of this has much to do with the thread's subject).
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on December 30, 2017, 06:04:31 am
Have you tested and confirmed the claim that directional sensing of an individual ear is mostly limited to the vertical plain?

Not formally. I was simply replying to Jim's post on sound localisation with information on sound localisation from a well regarded audio reference book I own which is now in its Seventh Edition.

How about trying this:

Rub your thumb against your index or middle finger, move it in the horizontal plane from front to rear, back to front: can you follow the rustling sound?
Do you get any less directional sense from rustling horizontally than making the same move in the vertical plane? I certainly don't. I hear them both equally distinct.

I tried it briefly but  realized it's not a blind test since I already know where I have placed my fingers. I cant be sure it's not that prior knowledge which is helping me to cheat a little. It seems to me a fairer test would be asking an assistant to make the sounds for me, and for me to be blindfolded.

 

(Not that any of this has much to do with the thread's subject).

As I said I was replying to Jim's post on sound localisation. And I took your earlier post about candy wrappers to mean microphones are poor at translating sound localisation information. Hence my earlier surprise that nobody had mentioned dummy head microphones in that context. For as we know they are specifically designed to preserve localisation cues. If you meant something other than sound localisation, fine, but in that case it might help if you explain what you did mean.

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 04, 2018, 05:55:57 am
But how would one measure "the sound pressure waves" for comparison except with a microphone?

As mentioned, here is the paper on measurement microphone calibration standards I referred to but temporarily mislaid.

Calibration of Pressure and Gradient Microphones by Victor Nedzelnitsky.

https://www.nist.gov/sites/default/files/documents/calibrations/eacous.pdf
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on January 04, 2018, 11:08:18 am
As mentioned, here is the paper on measurement microphone calibration standards I referred to but temporarily mislaid.

Calibration of Pressure and Gradient Microphones by Victor Nedzelnitsky.

https://www.nist.gov/sites/default/files/documents/calibrations/eacous.pdf

Thank you for sharing! I read the whole paper (though perhaps not a close, detailed read). A few things jumped out:

(section 2.1)

The paper acknowledges that there's no perfect way to calibrate a microphone, so that a calibration procedure must be selected to "correspond... to the pertinent critical conditions of intended use of the microphone" (section 3.1).

This is, of course, subjective and speculative in every case, because the testing procedure must account for the inherently subjective questions of "how is this microphone most likely to be used?" and "what's the appropriate way to measure for that application?"

For example, in section 4.1 uncertainties in the measurement of pressure sensitivities are detailed. It's acknowledged that discrepancies can arise as a result of such measurements being "critically dependent on different choices made in different laboratories with regard to rather complicated details of method and apparatus."

In other sections outlining other procedures, the reader is advised of several similar uncertainties and discrepancies.

All of the testing procedures outlined require the excitation of a second transducer of some sort (read: speaker or a second microphone), which can (read: most certainly will) introduce its own unintended characteristics to contaminate the measurements. The significance of these errors (or the appropriateness of methods undertaken to compensate for them) will, of course, be at least somewhat subjective (section 7.3 is also of particular interest here).

Also important is section 8, the only section to deal with the concept of phase (as opposed to just frequency response). This very brief section serves chiefly to acknowledge that (paraphrasing) the state of the art in calibration of phase response in measurement microphones is highly immature (at the time of writing), and that "there  must be further development of these primary standard methods."

This is crucial, because real-world experience has instilled in me a sense that phase errors and off-axis coloration may be as important as on-axis frequency response to a microphone's subjective performance.

The paper was first published two decades ago, so it's unclear whether any substantial advancements in the state of the art have occurred since its publication (I'd assume they likely have).

But I didn't personally come away from this paper convinced that there's any sort of universally agreed-upon standard and procedure for establishing what constitutes "accuracy" in a microphone. Remember, "best available information" does not necessarily correspond to "perfect information."

The paper outlines the best available procedures (contemporaneous to its writing) for evaluating measurement microphones. I'd be hesitant to ascribe more importance to it than that.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 04, 2018, 01:15:17 pm
Thanks for picking through the paper for the rest of us.
Unless I am mistaken, don't all these calibration methods rely primarily on sine wave reproduction? I.e. a singe tone is fed and the accuracy (yes, an appropriate use of the term in this context) of the response is recorded and compared.

I pointed out decades ago the fallacy of single-tone reproduction as criterium for the quality of a recording mic: The frequency graph accompanying a Radioshack condenser at $99 (this was when Radioshack was still in business) looked identical to a B & K measuring mic, or a top-notch studio mic by a major manufacturer: ruler-flat response, low noise floor... 

But I have found that the quality of a mic can best be judged with our ears: how that mic processes complex waveforms arriving at the same time: a timpani's spike, a violin's scratchy bow, a trumpet's overtones, etc. all at the same time. Is that multitude processed without smear? Does the soundstage collapse? Can I still pick out individual nuances of each instrument from the whole?

Tell me how you would measure the dynamic ability of a mic- processing complex events in real time, and "accurately". You cannot possibly get a clue from a rather primitive, static, sine wave feed, a frequency at a time?

What other device but our ears can judge a mic's ability in this regard?
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on January 05, 2018, 11:46:53 am
Another measurement error is the sine wave generator. That requires a form of speaker. Speaker distortion is a magnitude of error beyond the mic capsule's THD.

We end up measuring both with each contibuting to the errors.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 05, 2018, 07:15:32 pm
Another measurement error is the sine wave generator. That requires a form of speaker. Speaker distortion is a magnitude of error beyond the mic capsule's THD. We end up measuring both with each contributing to the errors.

Thanks Jim for bringing us back to this fundamental point, mentioned more than once earlier in the thread.

If speaker inaccuracies are a problem in calibrating mics they're even more a problem for listening tests. For we must listen via speakers or headphones.

With mic calibration work a special speaker called an "electrostatic actuator" is often used. It's really a high quality condenser microphone  used as a tiny speaker in a special closed coupler arrangement. Apparently it has the least distortion possible in a speaker or driver.

Even with a speaker as a source, with many distortions, two microphones can be used at once in the same coupler. If those speaker distortions are identical in both microphone outputs, and using another speaker, a different set of distortions are identically produced in the two mics, the distortions are quite validly assumed to originate from the speakers, not the mics, and since the distortions are now known, they can be subtracted from the result, revealing just the distortions of the mics. At least that's my understanding of it.

 But we can only "listen" to a mic via a speaker or headphone, with all its distortions which as you say are likely much worse than of the microphone. In a calibration test procedure we can validly cancel out the speaker distortions. Listening, we can't.
 
Once we put all our confidence in listening tests alone, ridiculing formal test procedures, we are tempted to pretend the speakers or headphones for listening aren't there. They seem a bit like the elephant in the room...



Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 05, 2018, 08:36:01 pm
Once we put all our confidence in listening tests alone, ridiculing formal test procedures, we are tempted to pretend the speakers or headphones for listening aren't there. They seem a bit like the elephant in the room...

You can land arguments better by dropping your snarky tone towards those who disagree with you.

Speaking of disagreeing, I see two fallacies in the two main arguments you bring forth in your post.

1. You write:

Quote
Even with a speaker as a source, with many distortions, two microphones can be used at once in the same coupler. If those speaker distortions are identical in both microphone outputs, and using another speaker, a different set of distortions are identically produced in the two mics, the distortions are quite validly assumed to originate from the speakers, not the mics, and since the distortions are now known, they can be subtracted from the result, revealing just the distortions of the mics.

Whereby you assume that "distortion" is some kind of single-factor event that can be mathematically deduced and removed from the test arrangement as per your recipe.

But I don't regard "distortion" as a linear or single-factor event, instead, it's the sum of all kinds of interrelated, interactive events: phase issues, frequency issues, delay issues, timbre issues, resonances, on and on. The model you propose, to cleanly "swap" out these anomalies and thereby deduce that they must have originated from the speaker is, I believe, incorrect.

But that is just a side issue, in my estimation.

2. The true "Elephant in the Room" as you call it, is your assumption that it makes sense to completely disregard the listener's (subjective, unreliable) judgement, when, after all, the listener is the ultimate target of any audio product. No testing chamber, no mathematical formula, no theoretically idealized approach, nothing ultimately matters but whether the listener likes what s/he hears or not. And that approach- manufacturers making splendid mics by listening, and listening to the listeners- has worked for many decades, giving us iconic mics that have spawned countless iconic recordings.

I find the engineering of audio products that exclude sensual feedback dystopian and soulless. As we know from those who go that route to achieve "accuracy" in their products, they have not found the degree of acceptance in the marketplace one would assume. 

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 05, 2018, 11:54:04 pm
"...the test arrangement as per your recipe."

"The model you propose..."


It's neither my recipe or my model. It's what I take to be normal procedures in testing laboratories all over the world. If I've read it wrong (it's not my speciality) I'm more than happy to be corrected.


The true "Elephant in the Room" as you call it, is your assumption that it makes sense to completely disregard the listener's (subjective, unreliable) judgement...

Actually I dont.

But to be specific, if a potential customer comes to you, a microphone expert, and asks you to test  his U87 mic whether it is still operating within factory tolerances, what do you do? How do you test it? If you have not the testing facilities do you send it off to a testing facility? What then is your attitude to formal testing of a microphone and why?

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 06, 2018, 12:21:51 am
(...)if a potential customer comes to you, a microphone expert, and asks you to test his U87 mic whether it is still operating within factory tolerances, what do you do?

We don't need to reach for a hypothetical "potential". For thirty years of "analyzing" someone's supposedly malfunctioning mic, I plug in and listen. I have never come across a case where that type of analysis did not yield a 100% positive result: a mic's defect either shows up by listening, or it does not exist.

Quote
How do you test it? If you have not the testing facilities do you send it off to a testing facility?
What "testing facility" did you have in mind? Did you think that Sennheiser, Telefunken USA, AKG, etc. use rocket science when they test a supposedly defective mic that comes in for repair?

I hope this isn't news to you, but, if the mic distorts, you'll hear it, if its noise floor is too high, you'll hear it. If its frequency response is odd, you'll hear it. As I always say: if the mic sounds right, it is right and healthy, if it sounds wrong, then it needs repair. There are no strata of cancerous developments hidden from plain listening, but that certainty of diagnosis sure does not come on day one of dealing in the matter. Neither does brain surgery.

Your belief in scientific diagnostics* of defective microphones may stem from your personal unfamiliarity and inexperience with microphones, and therefore may be more informed by images of lab coats, cleanrooms, oscillographs and HP Scientific Calculators. But, just between me and you: most of my colleagues at (companies shall remain unmentioned) do the exact same thing as I do, but they may be a bit more diplomatic about how they sell it, to keep the customer's belief in the superiority of objective science intact.

* OK, I lied. Some customers are so intent in having the diagnosis delivered in a scientific way, that I will actually sweep the mic (shitty methodology, for sure:) using uncalibrated speaker, sine wave, white noise generator etc. but at least it will give the owner a relative ± number of the deviation from standard, which make him happy.  (Not that this was ever necessary for me to diagnose and remedy the underlying issue, which is usually a contaminated capsule or defective capacitor.)
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 06, 2018, 06:18:44 am
My understanding is that at least with measurement microphones used for say industrial, medical, legal purposes it is normal, perhaps decreed  by law, to have the mics' calibrations formally tested on a regular basis, and to a  high level of accuracy.

Your belief in scientific diagnostics* of defective microphones may stem from your personal unfamiliarity and inexperience with microphones...

 My own experience of calibration was in the late 70's and early 80's when I worked as a technician in repairing and calibrating  hearing aids and annually repairing and calibrating portable audiometers (hearing testing units) to National Standards. The audiometers were used by school nurses to screen children for possible hearing problems. I took my calibration work seriously as I was trained to, and  adjusted each spot frequency (from 125Hz to usually 6000Hz) as closely as possible to the 0 (zero) reference on the B & K analyzer which was fed by the B & K Artificial Ear condenser measurement microphone.

I know of at least one recording engineer  specialising in acoustic classical recordings, who has his high quality recording  condenser microphones regularly and formally tested to confirm they are still performing within manufacturers' specifications.

 



Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 06, 2018, 07:37:10 pm
With mic calibration work a special speaker called an "electrostatic actuator" is often used. It's really a high quality condenser microphone  used as a tiny speaker in a special closed coupler arrangement. Apparently it has the least distortion possible in a speaker or driver
The "electrostatic actuator" isn't an acoustic sound source of any type, but a grid that can be mounted close to the diaphragm of a measurement microphone. It excites the mic by electrostatic force, then a (theoretical) correction curve for the sound pressure (treble) boost caused by the physical dimension of the mic is applied. The result is the the calibrated frequency response published by the manufacturer.

I don't think that harmonic distortion measurement makes sense this way (I might be wrong).

For distortion measurement on mic's the differential method is used.
2 different frequency sinewaves from 2 different soundsources are used at the same time and "mixed" acoustically.
The microphone does produce differential (not harmonic) distortions that are not present in the individual sound sources, which produce harmonic distortions only.
With exciting frequencies of, e.g. 10kHz from speaker one and 11kHz from speaker two, the mic's nonlinearity produces e.g. 11kHz-10kHz=1kHz.
Harmonic distortion of the sound sources don't matter this way.

This method can be used to measure extremly low electrical distortions too, as the (then two) generators don't need to be very low distortion types.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 06, 2018, 10:05:56 pm
The "electrostatic actuator" isn't an acoustic sound source of any type, but a grid that can be mounted close to the diaphragm of a measurement microphone. It excites the mic by electrostatic force, then a (theoretical) correction curve for the sound pressure (treble) boost caused by the physical dimension of the mic is applied. The result is the the calibrated frequency response published by the manufacturer.

Thanks for that correction Kai. I admit I didnt quite understand why in photos of the Electrostatic Actuator the "diaphragm" looked more like the mere backing plate of a condenser microphone!

On rereading 6.6  I now see Nedzelnitzky makes it plain. The relevent section is 6.2 where Nedzelnitzky does  mention using a reference microphone as a sound source.


I don't think that harmonic distortion measurement makes sense this way (I might be wrong).

For distortion measurement on mic's the differential method is used.
2 different frequency sinewaves from 2 different soundsources are used at the same time and "mixed" acoustically.
The microphone does produce differential (not harmonic) distortions that are not present in the individual sound sources, which produce harmonic distortions only.
With exciting frequencies of, e.g. 10kHz from speaker one and 11kHz from speaker two, the mic's nonlinearity produces e.g. 11kHz-10kHz=1kHz.
Harmonic distortion of the sound sources don't matter this way.

This method can be used to measure extremly low electrical distortions too, as the (then two) generators don't need to be very low distortion types.

Thanks for that. The heterodyne principle isnt it?

As I said this field is not my speciality so great to have your contribution.

Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 07, 2018, 04:09:41 am
On rereading 6.6  I now see Nedzelnitzky makes it plain. The relevent section is 6.2 where Nedzelnitzky does  mention using a reference microphone as a sound source.
This is another method, as far as I remember you compare 3 microphones this way to determin their sensitivity at a certain frequency, but I never dug deeper into that.
The heterodyne principle isnt it?
It's based on that underlying principle, widely used for FM radio receivers and high quality tone generators.
It's even called difference tone- or intermodulation- distortion measurement, IMD.
For IMD measurement often a combination of a low and high frequency like 60Hz and 7kHz with a level ratio of 4:1 (SMPTE IMD measurement) is choosen, the low frequency modulates the level of the higher one.
More details here:
https://www.ap.com/technical-library/more-about-imd/
In microphones most of us know this effect - during a strong pop noise (from a singer) the higher frequencies go down in level. If the low frequency is removed by a high pass filter the level modulation still remains.
These kind of distortions make the sound rough, they are present in every system with amplitude nonlinearities. The 2-tone method is just another way to measure the same thing.

For us it's important to kow that these types of distortions exist, for mixed signals like music a distorting microphone or amp doesn't only produce "harmonically rich" 2nd and 3rd order distortions, but all kind of "dirt" in form of sum and difference frequencies of ALL frequencies input.
Guitarist use that in their amps, and most of us will know how a 6-note guitar chord sounds through a heavy metal setting. That's why power rock chords (mostly 2-tone chords based on the 5th) are used, they don't produce dissonant tones when distorted.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 07, 2018, 10:00:24 am
Thanks Kai.

Re a  mic such as a quality 1/2" omni condenser from Neumann or DPA, can you say what are typical distortion figures, such as harmonic, IMD etc? What do you understand as the significant distortions (and their typical values) in such a mic generally, using the word "distortions" to include all deviations from strict linearity?

Regards
Tim
Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on January 07, 2018, 12:06:04 pm
There are papers from the AES Journal on this subject of THD of condenser capsules. I rcall one from 20 odd years ago exploring the effects of loading on the THD results.

Lower value loading resistors like the 200 meg ohms used in older tube mics will generate capsule THD in the lower frequencies. The article determined that a load of 10 gig ohms avoided the low frequency distortion many find subjectively pleasing on vocals.

The 10 gig values lowered the capsule THD to .001% at 50 hz.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 07, 2018, 02:07:00 pm
That's just THD. I regard any deviation from the original as distortion - distortion of the reality I perceive with my ears.   

Except there's no measuring strick for that, yet. And, as this discussion shows, it's not always easy to be heard on that level, as long as there is the belief that objective science has moved the needle towards better mics in the last five decades.

I am not anti-science. But I am anti cherry-picked science. Observation without limitation to methodology needs to be a central part of scientific investigation, especially when an observed phenomenon cannot yet be explained or quantified at the time of observation.

A good example from the audio field: interconnects all sound different, yet that difference cannot be fully explained in terms of capacitance, reactance, resistance, frequency response, etc.

And neither can inadequate copies of specific components, like M7 capsules, BV8 transformers, VF14 tubes, and so on, be sufficiently explained in scientific terms, to the point that their shortcomings could be overcome.

Here, again, and until further notice, ears are trump.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 07, 2018, 06:33:01 pm
There are papers from the AES Journal on this subject of THD of condenser capsules. I rcall one from 20 odd years ago exploring the effects of loading on the THD results.

Lower value loading resistors like the 200 meg ohms used in older tube mics will generate capsule THD in the lower frequencies. The article determined that a load of 10 gig ohms avoided the low frequency distortion many find subjectively pleasing on vocals.

The 10 gig values lowered the capsule THD to .001% at 50 hz.

Where very good low frequency performance was needed I understood that the Sennheiser Radio Frequency type microphone (MKH) was an important development.

But apparently conventional microphones including B & K measurement types appear to have accurate response (including low THD) to well below 20 Hz  and yet are not RF types. Can you shed any light on this? Did the input impedance of FETs improve for example?

Regards
Tim
Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 07, 2018, 06:51:42 pm
... interconnects all sound different, yet that difference cannot be fully explained ...
... Here, again, and until further notice, ears are trump.
If I can hear it but cannot measure it I do measure the wrong thing - not from me, but I consider this to exactly describe the problem.
Physics just has entered the area of quantum effects, and mic signals are so low that they may well be prone to those - just an idea and I have no evidence for this hypothesis.

I'm in the process of building a setup to measure extremly low distortions in electronic parts.
Currently I can measure down to -155dB and still trying to come down further.
My findings are already very astonishing: there are sources of distortion where you would not expect them and there are things that I always thougt could be a problem that aren't.
Specially connectors so far did not show up anything suspicious.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 07, 2018, 07:21:56 pm
With "interconnects" I did not mean connectors but the cables that connect audio components like mics, to mic preamps, and so on. (Maybe it's a term not familiar to the audio community outside the U.S?)

Quote
If I can hear it but cannot measure it I do measure the wrong thing

Agreed. And, in a truly scientific process, that point would be the start of further exploration, rather than premature speculation, that, what I cannot measure does not exist (how often have I read this on audio forums!)

Title: Re: The Myth of the Accurate Microphone
Post by: Jim Williams on January 08, 2018, 12:14:02 pm
The late Bob Pease of National Semiconductor did low level distortion tests on then new LME series of opamps because the traditional techniques of adding noise gain and extrapolating the results through an audio analyzer like Audio Precision didn't go down far enough to reveal the baseline distortion.

Bob ended up adding an Agilent network analyzer to the process to determine that opamp's true THD at -155 dbu. The LME49990 (now discontinued for no good reason) did even lower, almost -160 dbu.

This type of test does apply to a capacitor mic's active impedance converter/output drive but does not apply to a physical capacitor capsule as that requires different stymuli.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 08, 2018, 05:55:53 pm

 ...I have found that the quality of a mic can best be judged with our ears: how that mic processes complex waveforms arriving at the same time: a timpani's spike, a violin's scratchy bow, a trumpet's overtones, etc. all at the same time. Is that multitude processed without smear? Does the soundstage collapse? Can I still pick out individual nuances of each instrument from the whole?...

A wise rule is never to choose a complex explanation when a simple one can explain it just as well.

Many amateur music recordings are fine when only one instrument is playing but when all instruments play  together the sound blurs terribly. Is this because the mic struggles with the "complexity" of many instruments all playing at once?
Often it has little or nothing to do with that.

Quite rightly, a lot has been made here of listening, so here's a listening example, actually from a professional label of a major vocal performer. Admittedly this is from a live TV performance so we need to make allowance for that.

There are multiple audio problems with this presentation but notice what happens as the song progresses. Is it because of the added complexity of the multiple instruments, or is there a simpler explanation? What do you think?

https://youtu.be/uF5E0w2h6wM



 
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on January 08, 2018, 05:58:42 pm
A wise rule is never to choose a complex explanation when a simple one can explain it just as well.

On this we can agree.

For instance-- when someone asks "why is this microphone better in this application than that other one?" I'm much more likely to dispense with any objective or pseudo-objective justifications, and just say "it sounds better to me."
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 08, 2018, 06:59:28 pm
On this we can agree.

For instance-- when someone asks "why is this microphone better in this application than that other one?" I'm much more likely to dispense with any objective or pseudo-objective justifications, and just say "it sounds better to me."

I take it the person already knows or trusts it sounds better. They want to understand  WHY it sounds better.  How does effectively answering "because it does" help them?
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 08, 2018, 09:57:20 pm
Hey Tim,
RE: your reply #135.
When you quote something I said in post #118, i.e. 17 posts earlier, and don't fill in the context, it does not make for good reading or follow up.

WHY something sounds better than something else can be a big, and still largely unanswerable question. But it often has to do with an incomplete rendering by the mic of what we heard in the original. What's missing can be lack of proper processing of many impulses in time at certain frequencies (congestion), or a deviation in the dynamic processing of the original's behavior, or a lack of synergistic interplay of sound-shaping components within a mic's architecture...

Here is an example of the latter, and how misleading it sometimes can be to approach audio improvements by pure logic:
Take tube biasing. Nobody would make the argument that fixed biasing of the impedance converting tube in a condenser mic is superior for the noise floor and frequency response than self-biasing. So I experimented changed the fixed bias of a VF14 tube in the U47 mic to cathode biasing. The effect? Much quieter! Cleaner! Better highs! Yet, it sounded horrible on the scale of listener satisfaction. The dynamic behavior of the mic had turned anemic, its famous characteristics -heft, rich texture in the lower mids, a hyper presence in all the frequencies that matter for a singer, were all gone. It sounded like an audio engineer envisions a linear processor by means of a theory, without feedback from the ears. 

This is just one component in a mic of immense consequences that, once altered, no longer worked in sync with the rest (capsule, transformer, supply voltage, etc.)

We know from the mic's history, that at least some of its building blocks were haphazard, due to post-war shortages, and not what would ideally have made sense, yet the building blocks available fell into place and complemented each other in a most beautiful way.

That again tells me it's fallacy to assume an ideal path towards an ideal mic. The variables are simply to many and their effect on the whole too complex to leave mic design to measurable quantification alone.
 
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 08, 2018, 10:35:19 pm
RE:
Quote
There are multiple audio problems with this presentation but notice what happens as the song progresses. Is it because of the added complexity of the multiple instruments, or is there a simpler explanation? What do you think?

https://youtu.be/uF5E0w2h6wM
The mic channel is horribly overloaded on loud passages. So I am not sure how your audio sample relates to the point I brought up.

We don't play games here, where the pupil as homework has to find the answer for the teacher's question; so why don't you tell me how an overloaded vocal mic track relates to my point how poorly executed audio components collapse when too many complex waveforms arrive, and how that is hard to quantify and isolate in technical terms?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 09, 2018, 01:28:05 am
The mic channel is horribly overloaded on loud passages.

Yes the vocal is badly overloaded on loud passages. 

... why don't you tell me how an overloaded vocal mic track relates to my point how poorly executed audio components collapse when too many complex waveforms arrive, and how that is hard to quantify and isolate in technical terms?

Admittedly the Whitney track isnt the best example of the total effect, but generally in a recording which starts quietly with only a few instruments, and then more instruments come in later,  it would be easy to conclude that the cause of the later distortion is the inability of the recording equipment to handle the complexity of multiple instruments themselves. But correlation is not causation. Far more likely the equipment is overloading at some point in the chain due to the combined extra volume of all the instruments playing together, as in a symphony orchestra - or this Whitney remaster, although it's mainly only apparent on the vocal here.

Re the point about  complexity. As I understand it, the many instruments are already "mixed" in the air before they reach the recording microphone, or even our ear. It's now a composite waveform of all those instruments. Like A + B + C + D = X. The mic or ear only deals with the composite X. So long as the mic's fidelity is accurate enough for that waveform that's all that matters. If there's distortion due to the mixing of the various instruments I guess we should  blame the air...

Yes of course  poorly designed, or poorly chosen, or poorly positioned mics - or any other stage in the signal chain- can cause havoc in a recording. It only needs one thing to be wrong. In my experience it's usually less the equipment than  the operator, the "nut behind the wheel"  that causes most problems- as with this Whitney track. I believe today's audio gear, including mics, is fantastic, and  even music recordings made with care many decades ago can be very satisfying to listen to, so long as everything is done well and somebody hasnt messed it up somewhere along the way.

And this track only seems to underline your very important point about listening to the result. I have been a keen listener all my life. Thanks for listening to the track Klaus. I suspect we both have always been ardent listeners and always will be.

Tim 

 





Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 11, 2018, 05:00:57 am
Hey Tim,
RE: your reply #135.
When you quote something I said in post #118, i.e. 17 posts earlier, and don't fill in the context, it does not make for good reading or follow up.

WHY something sounds better than something else can be a big, and still largely unanswerable question. But it often has to do with an incomplete rendering by the mic of what we heard in the original. What's missing can be lack of proper processing of many impulses in time at certain frequencies (congestion), or a deviation in the dynamic processing of the original's behavior, or a lack of synergistic interplay of sound-shaping components within a mic's architecture...

Here is an example of the latter, and how misleading it sometimes can be to approach audio improvements by pure logic:
Take tube biasing. Nobody would make the argument that fixed biasing of the impedance converting tube in a condenser mic is superior for the noise floor and frequency response than self-biasing. So I experimented changed the fixed bias of a VF14 tube in the U47 mic to cathode biasing. The effect? Much quieter! Cleaner! Better highs! Yet, it sounded horrible on the scale of listener satisfaction. The dynamic behavior of the mic had turned anemic, its famous characteristics -heft, rich texture in the lower mids, a hyper presence in all the frequencies that matter for a singer, were all gone. It sounded like an audio engineer envisions a linear processor by means of a theory, without feedback from the ears. 

This is just one component in a mic of immense consequences that, once altered, no longer worked in sync with the rest (capsule, transformer, supply voltage, etc.)

We know from the mic's history, that at least some of its building blocks were haphazard, due to post-war shortages, and not what would ideally have made sense, yet the building blocks available fell into place and complemented each other in a most beautiful way.

That again tells me it's fallacy to assume an ideal path towards an ideal mic. The variables are simply to many and their effect on the whole too complex to leave mic design to measurable quantification alone.

That may be true with the vintage U47 but as I understand it, it's not nearly as much a problem with "non vintage" mics where tubes as impedance converters, and transformers for balanced outputs, have been superceded by FETs and balanced active output stages, unless one is wanting the particular distortions those  components  and circuits can produce.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on January 11, 2018, 08:13:18 am
William Bruce Cameron summed it up nicely, for me:

"Not everything that can be counted counts, and not everything that counts can be counted"
Title: Re: The Myth of the Accurate Microphone
Post by: leswatts on January 11, 2018, 03:09:09 pm
I've reread this thread, and have a few comments in the perspective of a microphone designer.
1) Microphones are not ears. While seemingly obvious, let's give a couple glaring examples

Room walls, nearby things like other microphones, and the like create resonances with nodes and antinodes. We're all familiar with things like bass suckout in the middle of a room when a speaker is along a far wall or corner.
The nodes/antinodes are usually represented as pressure data, but particle velocity (integrated pressure gradient) has nodes/antinodes too, but spatially opposite...That is a pressure node is a velocity antinode.

So let's say a series of pressure antinodes is picked up by an omni ( pressure) microphone or ear.
If we replace that mic with a velocity type (figure 8) it will pick up nodes at those same locations. Peaks and dips are transposed. This sounds completely different!
What about a cardioid? It's equally sensitive to pressure a velocity. So the pressure part picks up a peak, and the velocity part picks up a dip. The sum is 6 dB lower. Again, the sound is completely different from what an ear hears.
Does this imply we should all be using omni mics for best accuracy? No...the ear brain/headmotion localizing element is missing (even with one ear as Jim mentioned) so it also sounds different from what we hear.
These are not subtle effects, they are major.

The other point...about mics being measured with pure sine waves vs the effect with complex music signals.
Any complex signal can be represented by a sum of pure sine waves within an arbitrary interval. A simple
example is the dirac delta function. Think of it a a single infinitely narrow spike...kind of a perfect impulse response. If you add the sum of ALL simple sine waves in phase at that point the sum will be the dirac spike. Everywhere else there is cancellation. The sine waves have to have been always going and always will be going though. If they are started or stopped the sum will not be the single pulse.
Quantum mechanics was mentioned a few pages back, and this happens to to be an example of the QM
Heisenburg uncertainty principle.

So if any instrument does well with a sine sweep (with little nonlinearity) it will do well with a sum. You must have nonlinearities to have intermodulation.

Les
http://lmwattstechnology.com/
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 11, 2018, 03:29:50 pm
Microphones are not ears. While seemingly obvious, let's give a couple glaring examples(...)

I am not aware of any post in this thread that made that claim. Microphones, in my opinion, are an approximation of what we hear with our ears. In some cases that approximation- through clever engineering or random happenstance- gives us the emotional connection to the music, much like our ears can.


Quote
Any complex signal can be represented by a sum of pure sine waves within an arbitrary interval (...)
So if any instrument does well with a sine sweep (with little nonlinearity) it will do well with a sum.

If it's that straight forward of a measurement issue, why doesn't any of the mics which promise to be "accurate", or any of the interconnect cables that claim to be artifact-free and "without congestion in the mids" deliver?

You mention you are a microphone designer (if I got this right). Have you succeeded in engineering a mic that, while not as sophisticated in design as ears, at least delivers distortion-free (under any definition) audio?
Title: Re: The Myth of the Accurate Microphone
Post by: leswatts on January 11, 2018, 05:47:15 pm
Quote
You mention you are a microphone designer (if I got this right). Have you succeeded in engineering a mic that, while not as sophisticated in design as ears, at least delivers distortion-free (under any definition) audio?

Yes, I was a development engineer for Shure and Electrovoice. I now design my own line as well as mics for other companies. That includes Condensers, ribbons, dynamics, and MEMs.

None of our microphones are distortion free. By design.

The best spec mics we have are probably our B&K measurement standards. They generally sound horrible in the studio.

Condenser microphones with flexible diaphragms are inherently distorting due to radial charge movement.
Our piston motion MEMS don't have that problem.

There's science and then there's marketing. Most audio marketing is nonsense of course.

What we try to do is use our scientific knowledge to manipulate parameters to make products that sound good. None of them work like ears...that's not our goal. It's all about expectation bias.

We have a new modeling technology to assist us in that goal...there will be some AES papers about that.

Do we achieve our goal? Guess I need to loan you a mic so you can be the judge.
Right now i'm on winter vacation on a sailboat so all I can do is show you a clip.
I owe one to Sound on Sound for a review too.

I write papers and books (and drink rum) on the boat in winter then return to the acoustics lab at springtime.
Call it semi retirement.

http://lmwattstechnology.com/microphone/polyribbon/soundsamples/soundsamples.html

Les


http://lmwattstechnology.com/
Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 11, 2018, 07:23:14 pm
Microphones, in my opinion, are an approximation of what we hear with our ears. In some cases that approximation- through clever engineering or random happenstance- gives us the emotional connection to the music, much like our ears can.
To me a microphone is quite similar to a photo camera, and a recording similar to a photograph.
The photograph will never be the same as the beautiful woman that has been pictured (or would you like to have a date with a photograph 😀?!), but in some cases she might even look better on the photograph than in reality.
This relativates the question if there is a perfectly accurate microphone. What would that accurate microphone deliver?
Is that microphone that makes a strong connection to the music really accurate or just a way to make a very nice looking photograph?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 12, 2018, 06:13:40 am

This reactivates the question if there is a perfectly accurate microphone. What would that accurate microphone deliver?
Is that microphone that makes a strong connection to the music really accurate or just a way to make a very nice looking photograph?

I think it's helpful to distinguish between "accuracy" and "what sounds good on a released recording", but these days there is no need to "choose" between one and the other.

So why use a recording mic as EQ  when we have far more sophisticated dedicated EQ at hand later on? Similar with adding  euphonic distortion such as from tubes or transformers. These things are far better applied and controlled using those tools as  separate steps after the initial recording is made where we can take our time and finesse the sound. The beauty of multitrack recording (from the 50's) and even more so, digital recording was that it allowed each step to be done without compromise, rather than having to get everything finalised at the initial recording take.

In other words, in recording, we can have the best of both worlds. With the mic we can  capture a vocalist cleanly, optimally, even (dare we say it) fairly accurately but it doesnt have to be "the finished product" straight off the mic. It's a very important step and must be done well, but still it's only the first step.
 
Title: Re: The Myth of the Accurate Microphone
Post by: leswatts on January 12, 2018, 07:44:11 am
Quote
To me a microphone is quite similar to a photo camera, and a recording similar to a photograph.

The photography analogy is a good one. When I watch an old movie I want to see the garish color and contrast distortion of technicolor. I don't want to feel i'm on the movie set.

Quote
This relativates the question if there is a perfectly accurate microphone. What would that accurate microphone deliver?
Is that microphone that makes a strong connection to the music really accurate or just a way to make a very nice looking photograph?

This is the 21st century, not 1935 or 1980. Electroacoustics is not a mystery to us. We can capture
a sound field at a point accurately enough that any anomalies would be inaudible except for noise.

To me approaching that state results in disappointment with most. My customers want something "bigger than life"...not reality. If they wanted reality we'd give it to them.
At Shure we did many many listening tests...some scientific some not. As we approached results with very good numbers we all learned of the characteristic dull sound it produced. We tried to get that high performance in our products, and were often criticized for it. Personally I prefer accurate sound, but i'm not a customer.
 
The mystery is quantifying "bigger than life" so we can engineer it into a product. We have to turn emotion into math.

Part of that is not electroacoustics. People will hear good things because the product is old, rare,  fragile,expensive, has platinum wires, or is red instead of blue. We accept that.

It doesn't have to be that way though...Moore's law works with microphones too. Most microphones made now are silicon chips made by robots.Billions of them.

Soon the robots will make everything (including the best microphones) and all will be free. No one will have to work. All our needs will be met.

The plutocrats will try to prevent this of course.

Les
http://lmwattstechnology.com/index.html
Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 12, 2018, 10:00:52 am
We can capture a sound field at a point accurately enough that any anomalies would be inaudible except for noise.
But that single point of a larger soundfield does not even come close to represent the real event that caused it, so why chasing after the idea to capture it accurate.
And even if you did the impossible and captured the real event inside a recording, playback on loudspeakers doesn't reproduce it.
Whatever you do you end up with only a picture of what happened, so why not concentrate on making this picture look as good as possible without taking the constraints in trying to make it accurate, only to end up with a bad recording?

So many times I had the practical experience where bands came into my studio that had done recordings in the so called audiophile field, with just a stereo microphone in front of the whole band because someone had the idea that this is "accurate".
These bands where astonished and pleased when they heard, for the first time, how good they could sound on a serious recording.

This does not mean I cannot make very good recordings with just a single stereo microphone, but the circumstances must fit.
E.g. I'm going to do such a recording tomorrow, and I will use a single pair of Neumann KM84s, because, on that special event, they have proven to give me the best sound of all that I have in my collection.
I would not consider the KM84 an accurate microphone, but a good sounding one on many occasions.
Title: Re: The Myth of the Accurate Microphone
Post by: leswatts on January 12, 2018, 11:59:38 am
Quote
But that single point of a larger soundfield does not even come close to represent the real event that caused it, so why chasing after the idea to capture it accurate.

Exactly. But that's all a single microphone can do. Most don't even do that, because you have to capture pressure (a scalar) and particle velocity (a vector)to define the sound field at that point.We can do that with a MEMs array.

I work with a firm that does microphone modelling...and the big issue is that loss of directional information. A mic has different response with direction, and you can't simulate that with eq or dsp
when direction is lost. it's a big part of microphone sound.

I like the KM84 as well, although I wouldn't consider the charge amp like configuration particularly hi-fi.
We make something similar but use a cascoded jfet with complimentary bipolar follower driving a transformer. We don't bootstrap the drain, so there's a little on purpose low order THD from Cgd.

Les
http://lmwattstechnology.com/
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 12, 2018, 10:00:40 pm
...So many times I had the practical experience where bands came into my studio that had done recordings in the so called audiophile field, with just a stereo microphone in front of the whole band because someone had the idea that this is "accurate".
These bands where astonished and pleased when they heard, for the first time, how good they could sound on a serious recording...

Hi Kai, just to clarify, what do you mean by a serious recording here?  Do you mean for example many close mics on instruments and later mixed?

Tim

Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 13, 2018, 05:27:45 am
what do you mean by a serious recording here?
For me a "serious" recording is not just connected to the technical aspects, but to the result.
The so-called "audiophile recordings" mentioned had nothing positive in them. Due to the lack of working with the musicians there were a lot of mistakes, the sound was distant and intransparent and so on...
This isn't a musical recording, but just the fulfillment of a philosophy of people usually not in contact with professional audio recording.

Everybody agreed that what I did with those ensembles is worlds apart from what they had before. For one of them the recordings opened the door into a completely different world, making connection with famous acts and musicians. I have had connections with most of these musicians and bands ever since.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on January 13, 2018, 09:51:10 am

So why use a recording mic as EQ  when we have far more sophisticated dedicated EQ at hand later on?

I'd ask a different question: "why accept the tradeoffs of manipulating the signal with an EQ when there's already a microphone that sounds how I want it to sound?"
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 13, 2018, 06:05:20 pm
I'd ask a different question: "why accept the tradeoffs of manipulating the signal with an EQ when there's already a microphone that sounds how I want it to sound?"

If we're happy with the sound straight off the mic, yes why change it?

But if you're expressing an opinion as to the possible deleterious sonic effects of EQ in general that would seem to be a separate issue deserving of a discussion in its own right.

Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 14, 2018, 08:04:08 am
So why use a recording mic as EQ  when we have far more sophisticated dedicated EQ at hand later on? ... better applied and controlled using those tools as  separate steps after the initial recording is made...
The sonic differences between microphones cannot be reduced to a question of EQ or other electrical parameters that can be reproduced or changed later.
This is why proper microphone selection and placement plays such an important role for achieving a good sound.

On the other hand mic selection and placement, combined with EQ, largely enhances the number of choices and possibilities.

E.g. You can use a slightly dark sounding ribbon mic as drum overhead because of it's special accoustic qualities and partner it with EQ for the bit of missing treble - a common practise.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 14, 2018, 09:52:45 am
The sonic differences between microphones cannot be reduced to a question of EQ or other electrical parameters that can be reproduced or changed later.

I'm not sure what you mean by that. Certainly on axis frequency response is only one aspect of a mic's performance although a very important one.
Brad seemed to imply EQ has such a deleterious effect on the sound that it's best to avoid its use by instead "EQing with the mic". I suggested the question of the transparency of EQ is another subject on it's own. That was the context.

This is why proper microphone selection and placement plays such an important role for achieving a good sound.

Agreed!

On the other hand mic selection and placement, combined with EQ, largely enhances the number of choices and possibilities.

Agreed!

E.g. You can use a slightly dark sounding ribbon mic as drum overhead because of it's special acoustic qualities and partner it with EQ for the bit of missing treble - a common practise.

What are the "special acoustic qualities" of the ribbon that are relevent here to its role as a drum overhead? Its bidirectional pattern with deep nulls at 90 deg? Its wide, smooth response? Its relative insensitivity which is not so much an issue with a loud source like a drum kit? Is the slightly dark response important to the sound here or merely a problem that needs to be corrected with some EQ later on?

It helps to be specific so people understand the  principles and can apply it correctly whenever a similar situation comes up.



Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 14, 2018, 12:16:52 pm
I'm not sure what you mean by that. ....
You're right, my quotation was stupid, I did mean the above and changed my post accordingly.
Let's delete this to keep the discussion clear.

What are the "special acoustic qualities" of the ribbon that are relevent here to its role as a drum overhead?
There is a certain softness in the sound that you should hear, best by AB-ing with your "standard" condenser drum overhead.
The room pickup is much different too, even compared to figure of eight condensor mics.

I have several other favorites for drum overhead too:

- Schoeps CM640 "speech cardiod", tube version, with LF rolloff and strong treble boost built-in, delivers an almost "mix ready" sound on many occasions.

- AKG C451/CK1s, cardiod with treble boost, bit harder to find a good placement, gives a good starting point for the mix.
Very good to use them as tom mic's that are serving as cymbal "under-heads" at the same time.
Using those I can pick a small kit with only 5 mic's: Kick, Snare, Hihat, Floor Tom, one or two Rack Toms.

-AKG C414, a workhorse, nothing special, always on the soft side with strong LF. Un-EQed giving a complete picture of the drumset.
Needs more or less EQ, largely depending on the exact model variant.

- Bruel & Kjaer (now DPA) 4004 or 4006 with diffuse field grid, omni with treble boost (DF grid). Very clean, the room and the drum kit must fit. Nice for Jazz, as "main"-mic.
Especially the 4004 could be considered as a technically "accurate" mic this discussion is dancing around. The DF grid makes it less accurate, but better suited for the purpose.

- Shure SM57 (select a good one) as mono center fill, can take more or less of fast compression, add a little in the mix for fuller body and depth.

 
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 14, 2018, 12:51:40 pm
I am not into enlarging the original topic to "what mic works best for what purpose".

All the examples given for a suitable color palate of choices in the recording studio, including, curiously, models of mics that purport to be accurate, confirm what I said all along: there is no consensus that ONE "accurate" mic would be ideal to have, superseding all other "colored" choices:

"Accurate" does not exist, cannot be scientifically confirmed, and, despite being hyped in the market place, seems undesirable for the vast majority of users.

Are we done with this subject?
Title: Re: The Myth of the Accurate Microphone
Post by: Kai on January 14, 2018, 01:36:18 pm
I am not into enlarging the original topic to "what mic works best for what purpose".
This wasn't so much meant as cookbook suggestions, but as examples to bring theoretical ideas, EQ or Non-EQ, postprocessing, back into a practical context with something most of us have experience with.
Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 14, 2018, 03:53:53 pm
Understood and agreed.

So the summation is still this: in the absence of accurate mics and all other accurate components in the recording chain (don't even get me started on digital processing!), good engineers with good ears and experience choose recording tools that translate their idea of best representation of the music. Whereby "best" could be translated as "most emotionally impactful for the listener in a positive way".

It's quite revealing to realize how few of these recording tools we keep coming back to, regardless of type of music to be recorded. And how universal our esthetic therefore must be.
Title: Re: The Myth of the Accurate Microphone
Post by: soapfoot on January 14, 2018, 07:27:32 pm
Brad seemed to imply EQ has such a deleterious effect on the sound that it's best to avoid its use by instead "EQing with the mic".

I certainly regret if I seemed to imply that.

EQ doesn't necessarily have a "deleterious" effect, but it does have a host of effects, some intended, some unintended.

I am certainly unafraid to use an EQ if it's what I want. But it doesn't substitute for choosing the right microphone, in my opinion.

Equalization is a useful tool. It is not, however, a panacea, nor is it a substitute for an appropriate mic choice (and placement).

Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 15, 2018, 02:38:11 am

Equalization is a useful tool. It is not, however, a panacea, nor is it a substitute for an appropriate mic choice (and placement).
Agreed. But some performers (perhaps especially those unskilled in audio production) seem to wish for the reverse:  a mic that "does it all for me", a mic that is  a panacea or substitute for every production process that takes place downstream of the mic.

A mic that has been "personalised to the sound of my voice" might be very attractive to a performer who  knows or cares little more about audio than the microphone they sing into...

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 15, 2018, 03:23:32 am
A mic that has been "personalized to the sound of my voice" might be very attractive to a performer who knows or cares little more about audio than the microphone they sing into...
What does "cares little more about audio than" mean? Someone who cares little, or who cares more?

Actually, re-reading this sentence in full, I admit, I don't understand at all what you are trying to say.
Can you rephrase please?
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 15, 2018, 05:27:46 am
OK will have another try.
I'm sure the said performers do care very much that the end result is excellent but not being experts in audio production they have to trust that the audio personnel they deal with are experts in their field, will give them sound, reliable advice and aren't taking advantage of the performer's weaker knowledge.

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 15, 2018, 02:17:58 pm
Before I responded, I wanted to make sure that you really meant what you wrote. And I can tell you that I know of very very few professional singers who are ignorant about the recording process to the point that they do not care how their voices translate in the studio.

Most of my clients are so deeply engaged in the recording process, they not only actively select the mic from teh studio's locker, but bring their own vocal mic to the sessions (like you would expect from instrumental performers at any professional level: Itzhak Perlman or Pinchas Zukerman don't go to the local rental shop before hitting the studio).

On a general note:

Internet forums allow all of us to mix it up with the big boys by pretending to be experts, without anyone checking at the door. Reading your many posts in this thread so far, I am curious what practical experience you have in the professional recording world?

What you have shared so far (a lot of wikipedia and other experts' citations) makes me wonder what you do for a living? Where can we hear your recordings? What are your achievements in the recording business? What mics do you use every day?

Expert knowledge is not required for most subjects on this forum. Novices are always welcome, and the level of accomplishments does not matter. But the discussion of accurate mics is not enriched when posting without extensive personal experience.

Title: Re: The Myth of the Accurate Microphone
Post by: klaus on January 15, 2018, 02:40:58 pm
Mike Rivers wrote in another forum the following, which I found interesting, and which I am quoting with his permission:

Distortion is about many things, not just about harmonics of the source coming out than what went in. Most of the difference between source and mic output is a result of mechanical resonances and uneven frequency response. Generally when you see a THD measurement of a mic, it's of the electronics alone, and doesn't include the capsule.

Making high resolution acoustic measurements on a mic is quite difficult. First you need to be able to create a sound wave in air that has an order of magnitude less distortion than the mic you're trying to measure. Then there's contributions from external noise sources that must be dealt with. There's an IEC recommended test setup that a few manufacturers have built that looks a bit like a bomb with electrical connectors.

The AES working group on microphone standards has been trying for years to come up with ways to standardize measurements.
Title: Re: The Myth of the Accurate Microphone
Post by: Timtape on January 15, 2018, 08:31:46 pm
Before I responded, I wanted to make sure that you really meant what you wrote. And I can tell you that I know of very very few professional singers who are ignorant about the recording process to the point that they do not care how their voices translate in the studio.

And as you know I clarified my statement :  "...I'm sure the said performers do care very much that the end result is excellent, but not being experts in audio production..."

Most of my clients are so deeply engaged in the recording process, they not only actively select the mic from teh studio's locker, but bring their own vocal mic to the sessions...

Yes perhaps a different world from that of say the 1950's.
Sometimes it seems like nowadays everybody's an expert.