R/E/P Community
R/E/P => Klaus Heyne's Mic Lab => Topic started by: Timtape on May 23, 2013, 05:27:46 AM
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Hi,
I've been recently told that the frequency response graphs published by microphone manufacturers have been "smoothed" such that they do not reveal the whole picture with the mic with respect to narrow band peaks and troughs in the mic's response.
Is this so? Or is it possible that the resultant plot is perhaps a valid averaging of a number of "snapshots" of the mic's response perhaps to a calibrated but necessarily "bouncy" pink noise source in the anechoic chamber?
Thanks for any help or leads in understanding this.
Regards,
Tim Gillett
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I have a "compute smooth" function in my Audio Precision analyzer. It does as you suggest, smooth out bumps in the response. One pass, not too much. Run enough passes and any curve can get converted to a straight line. It's sort of like stretching a loose hose straight.
Measuring high frequency response on a mic is not easy to do. The source stimulus may have bumps. The measuring mic may have bumps. The room creates bumps. The DUT also has it's own bumps, the ones you are attempting to isolate. All of those errors add up and adds stuff to the measurments.
Whether the curves are accurate or "wishfull thinking" I leave up to the consumers to decide.
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I have come to the conclusion that looking at a manufacturer's response graphs of microphones is a fool's errand:
* There are no universally agreed-upon standards of measurements which all manufacturers would submit to, so that a consumer could compare mic graphs from different manufacturers.
* The allowed tolerances of frequency deviation are usually represented in the graph by two lines (for example, look at Neumann's owner's manuals): the response can then vary between these two extremes, at any point of the frequency response. With a ± 2dB range, for example, you can theoretically have a spread of 4dB between any two points on the curve-this could be quite an audible jolt.
* Smoothing the curve of the actual frequency response of an individual mic can be a reasonable marketing strategy, particularly when the buying public equates smoothness with quality (which, again, is partially the manufacturers' fault): If you were to base your purchase solely on the jagged lines of an ELA M 251's frequency response curve, you would look elsewhere.
Which brings up my main objection to publishing response curves, smoothened or not: They do not predict the quality of a microphone for musical recording purposes. As a mic is nothing better than a poor simulator of our quite sophisticated hearing, euphemistic aberrations in the response curve can, and in good mics will, make up for the technical deficiency of the device. A bit of a boost at the exact spots, a bit of a cut at some other precise frequency points add up to us liking the music better, or rejecting the mic altogether as "unmusical". You need look no further than a B&K industrial measurement mic with its ruler-flat response to prove that point.
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Thanks for your responses Jim and Klaus. Klaus, not sure what you are saying about B & K industrial measurement mics. Are you saying that effectively they are "ruler flat" compared to other recording studio mics or that even they have audible narrow band peaks and troughs?
The question relates to what is possibly a modern practice where engineers try a collection of high quality vocal mics on the one vocalist, before settling on one which, just to their ear complements that vocalist the best. Not so much because of broad differences in emphasis such as a mic with a broad presence peak re one that doesnt have one, but to hit on a mic whose narrow band peaks and troughs work better on that vocalist.
I have some reservations about the practice, especially when it then expands to people recommending certain mics fror certain genres of music such as jazz, pop, crooning, rap etc. Frankly I dont see the connection between a mic and a music style. Obviously a valid exception might be the use of a D type EV mic designed to minimise proximity effect when close micing but that would seem to be a special case.
I've seen this approach in recording magazines aimed at the home recordist who may not necessarily have such finely honed listening skills to be able to hear such anomolies between top quality mics., but still be tempted to buy a closet full of top quality mics in the hope that he might just hit on the "magic mic" for a particular vocalist. I certainly doubt that I could reliably pick differences between mics and mic samples which may be quite small and subtle, and I think I have pretty good listening skills.
Your thoughts?
Tim
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Tim,
I agree with you assessment: to pigeonhole a mic for a whole genre of music strikes me as superficial.
As to your question about B&K measurement mics: these types of mics are made to be as frequency linear as humanly possible, to detect non-linearities in acoustic events they are measure. Yet all that finagling to reign in tolerances and flatten the response makes for lousy music recording, I find (and the lack of acceptance in the professional recording community seems to confirm my observation).
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I believe one can make some generalizations about certain microphones vis a vis certain music styles... and they'll just be generalizations. E.g., female pop ballads tend to have airy, breathy vocals, and while the singers may strive for that sound, certain microphones also accentuate it. Doesn't mean that a C12 or C800 will be ideal for any particular singer, but that knowledge should help one find a starting point, or at least to discourage trying a Coles 4038.
This is a part of what makes an experienced engineer: knowledge of their tools and the genres of music they are recording.
And yes, the typical home recordist will be foolish to spend large amounts of money in pursuit of the "perfect" mic for their needs. That won't stop manufacturers, salespeople and magazine ad executives from encouraging the practice.
Yet I would argue against Tim's assumption that "...the home recordist... may not necessarily have such finely honed listening skills to be able to hear such anomolies between top quality mics." Given a decent listening environment, the differences are not necessarily that subtle. While a frequency response graph is not likely to be meaningfully informative about mic choice, a brief listening test will be.
And in the end, it is mostly about taste.
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B+K, (now under the DPA name) also makes music recording mics. The 4003, 4006 and the newer 4011 unidirectional are well recieved mics in the industry.
MA Recordings (Todd Garfunkle) uses a matched set of 4006 mics. Others that have used them include George Massenberg and many more.
Those are not flat mics, they have a 3 db peak at 16k hz, I find that annoying. They also have a slight metallic overtone due to the metal diaphrams.
There is far more to consider than simple response curves when selecting a mic. Noise, THD, IMD, linearity, bandwidth, slew rate are all factors, many involve the electronics past the capsule. A microphone is a system, not just a capsule.
Others also make measurement mics like APEX in No. Cal. Most are 1/2 or 1/4" diameter capsules, omnidirectional. That alone limits their use in a recording situation. Follow one with a great EQ and you can create the curves you like instead of the microphone designer.
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Thanks for your replies. The question as to whether high end mics have the audible narrow band non linearities was because this was given to me as the reason why such mics apparently sound different on different vocalists, and that engineers test out various top mics, which otherwise might be expected to sound very similar, on a particular vocalist before settling on one as subjectively sounding better. Sorry for the longish sentence!
What interests me is whether this subjectively superior sounding mic and vocalist combination could be verified by say 10 engineers all listening independently to the same combinations of mic, and vocalists and independently coming to the same conclusion, that is, the same mic for that vocalist. I wonder if it has ever been properly tested, or whether it has just been assumed that it has been established beyond doubt. Something about the subjective and the objective I guess.
Cheers Tim
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Why make it so complicated? If the producer/engineer chooses the right mic for the right artist, the results will be so stunning that you and I and a million other listeners will hear the difference, even while driving in our cars listening to the shitty car stereo, and we all will be drawn into the voice and many of us will then go out and buy the record.
And if every engineer had the money, they all would pretty much end up with the same five mics. And 95% of all voices would be covered by the same five mics.
An example for how obvious the right mic on the right voice is, and how there would probably be very little deviation in opinion, at least among professional engineers, about that choice: 'Skyfall' sung by Adele.
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Am I making it so complicated? Just the opposite, I'd suggest.
I recently suggested to a group of people that one excellent vocal mic would be fine for any vocalist in the world, in the hands of an expert. I received howls of protests and was told I knew nothing. Yet I suspect that for decades one top vocal mic would have sufficed in top recording studios worldwide.
With your Adele example, I respectfully suggest it's untestable for we have no recording of that song using another mic. It's not obvious that other top mics could not have done just as well.
Regards
Tim
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If a manufacturer provides individual plots for each example of a microphone sold, with the measurements done under the same conditions, that may be of some marginal utility in verifying that a pair is matched well for stereophony.
Otherwise, I have little use for such documentation. The best tools for selecting a microphone to use on a particular source are ears and experience.
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Sure. So if we had access to the same recording of Adele or anyone else, made with a similarly top vocal mic, we could put them side by side and use our ears and experience to judge how the alternative mic stacked up against the the mic which was used for the commercial release.
Without that, we have no "ears and experience" basis for comparison and so, I'd suggest, we are acting on faith.
Tim
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Acting "on faith" is not necessary when it comes to good sounds. An experienced engineer or producer knows the palette.
As for someone less experienced: just listen, then decide whether you like what you hear. If you like it, investigate the components that created the recording. And among those, the mic always stands out as the most crucial, sound shaping link in the chain.
And in the case of Adele, it is quite obvious to me, and probably to most other people who are experienced with microphones, that no other mic but an ELA M 251 would have been able to render her powerful passages as beautifully and harmonically rich as it did her intimate, soft passages in the same song.
Or put another way: If I did not know what mic was used in a seminal vocal recoding like that, I'd go investigate, find out, and save my pennies. A mic like that will carry you through in 95% of all cases (hence the hefty price tag).
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The first link in the chain is not the microphone but the singer, the voice, the song, the performance. I read this comment about the 21 album: " If the chain has Adele in it, its going to sound really really really good. You'd need some seriously shoddy equipment to screw that one up." An overstatement of course but I see the point nonetheless.
If you can use the one mic for 95% of vocals, is that because that mic is "shaping the sound" or because it is not shaping the sound, and is rather just rendering the performance faithfully to the audio recorder?
On dynamics, sure the mic must capture those faithfully but from there it's a production choice as to how to render those dynamics in the final product. Significant compression - whether manual or automated or a combination - was used downstream on Adele's dynamics, as it often is on dynamic vocals. Or was it upstream? Does Adele physically back off from the mic in louder passages? If so that is not the mic giving that effect. In an interview about the Adele sessions the producer also mentioned tape emulation plugins, a plate reverb and perhaps other FX, although apparently he often passes on the stems to someone else to do the mix and then to another person for mastering.
How did you know the ELA M251 was used on the Adele sessions? Did you work that out just from listening to the track or did you find out from other sources?
Tim
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All good points to discuss. I will respond after the holidays.
Best,
KH
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Another thing worth mentioning is that frequency response is but one factor in determining how a mic will sound.
At a minimum, there is also the time domain to deal with... i.e. the question of "does any part of the system create leading or lagging phase shifts at some frequenc(ies) or another?"
Other possible questions: how does a mic respond to and recover from transients? How, if at all, does its behavior change when in demanding applications?
But honestly, in application/use, all this stuff becomes pretty useless (to me) to think about intellectually. Art is a sensual enterprise, so you select the tool or color that gives you the result that you emotionally respond to, or the one that allows you to work quickly enough to capture the performance you emotionally respond to. It really needn't be more complicated or objective than that.
There's a time and place for comparisons and "shootouts," too, and for me that time and place is usually NOT in the middle of a session. From a production standpoint, I personally do not like to interrupt a creative flow by auditioning a bunch of microphones on every source. Sometimes, a session can be logistically planned to allow time at less-inspired periods for such "housekeeping," but for those times when there's a creative 'flow' happening, it can be better in my experience to just put something up and roll. Over time, the aggregate of experience leads one to predict what will likely work well, or narrow it down to one or two. I personally would much rather capture the best performance on the second-best microphone than the other way around.
So yeah, my mentality is to learn as much as possible about the characteristics of different microphones so that I as a producer may work with the engineer to make sound guesses in the heat of battle. But to me, this learning is best done experientially first, and intellectually a (distant) second.
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"Best mic for that singer" is one of those old wive's tales I hear repeated every few years.
What choice is best? Most accurate, or one that adds a little "something" someone subjectivly likes? Which 'chief subjective judge' makes the final decision? The artist, the producer, the label?
Many times I have had to switch mics on the same singer when the key changed just to retain some consistancy between tracks. Sing in G and maybe you found your "magic mic". Change to C and all that goes out the window.
As for Adel, although she's not my cup-o-tea I believe that any decent mic would do the job well. So it goes with good talent.
This reminds me of one day back in 1980 when I was on tour with Stevie Wonder. Me, Steve and Calvin walked into the huge, all tiled restroom in the old Boston Garden, home of the Celtics. Steve was doing vocal warmups, scales and things. The tone on his voice was amazing. While standing next to him at a urinal, I said, "Wish we could get that sound back at Wonderland". Steve turns and says to me, "tell me about it".
That day I learned that there is no microphone, nowhere on this planet, not at any cost that can sound as good as Stevie, as that is where the magic comes from. Everything that follows is a lessening. Work with that level of artist you will learn that too. Recording is a compromise. To me it's an exersize in controlling losses.
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The first link in the chain is not the microphone but the singer, the voice, the song, the performance.
I thought I made it clear that with "recording chain" I meant equipment and components. Sorry if I was not explicit.
I read this comment about the 21 album: "If the chain has Adele in it, its going to sound really really really good. You'd need some seriously shoddy equipment to screw that one up." An overstatement of course but I see the point nonetheless.
If the point is: "no matter what mic used, she will always sound fabulous" I'd reply: no, she won't; and she or her producer, faced with "shoddy equipment" (i.e. mic, for this discussion) will fire the studio, engineer, or whoever else made her voice sound less that spectacular.
And here we come to the core issue: the art of recording. The art of choosing the right mic will elevate most artists from competent to special, and from special to spectacular in some cases. A case in point: as far as I know, Frank Sinatra has never used a U67, despite its ubiquity in professional studios. He would not sound very authoritative with such a choice. Another case in point: I helped a famous singer with plenty of platinum sales under her belt transition from a U47 to an M49, because that mic complemented her strong points and suppressed some of the stridency in her range. She never went back (this was 20 years ago).
If you can use the one mic for 95% of vocals, is that because that mic is "shaping the sound" or because it is not shaping the sound, and is rather just rendering the performance faithfully to the audio recorder?
Given the fact that a mic is but a poor simulation of how we hear, I want from a mic what it can actually deliver: an ability to simulate and euphemize, to the point that it enhances my listening experience, "reality" be damned. Yes, a mic can simulate reality to a small degree (i.e. recognition that what I am hearing resembles a real source), and making the musical event connect with me emotionally, by choosing the right equipment and complementary signal chain. That process, in the hands and ears of an experienced professional, will render a euphemism, and it will be arrived at mostly by intuition (read nobturner's eloquent post), just like that of the pit boss of a racing stall at Le Mans choosing the right tire composition for a race, depending on a multitude of factors.
On dynamics, sure the mic must capture those faithfully but from there it's a production choice as to how to render those dynamics in the final product.
I don't know of any vocal recording whose dynamic range was not severely reduced, compared to the actual range of the singer.
As to other sonic manipulations that you believe could alter the character of a mic to the point of total loss of recognition: not really. You can at best retain the character of a mic during the production/processing stage, but you cannot fundamentally alter it and retain quality. We know this from the dismal failure of mic emulators' promises.
How did you know the ELA M251 was used on the Adele sessions? Did you work that out just from listening to the track or did you find out from other sources?
I don't really know. (I sent the producer an email). But it has the hallmark of that mic- an overall timbre, and type of overload on very loud passages I think I recognize (and love).
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Thanks for the responses. Too much to respond to in one go so I will just reiterate the main issue.
Basically I question the notion that 10 top producers would independently of each other, all choose the same vocalist and mic combination. I'm happy to be shown conclusive evidence that they consistently would, but without that evidence, I regard it as verging on, as one person might call it, "magical thinking".
Recently I got myself into forum hot water by pointing out that in a "mic shootout" conducted by a well know magazine, the expert listeners came to the same agreement as to which mic suited which vocalist, after a group discussion, rather than casting their choice secretly and independently.
From a practical point of view, I encounter many novices on forums who have all sorts of audio problems which often turn out to be unrelated to the mic, and yet the number of times they mistakenly implicate the mic suggests there is some basic misunderstanding going on here.
A chain is only as good as its weakest link. Sometimes that weakest link is the mic but often it isnt. The weakest link may not even be gear related at all but rather lack of skill and technique in using what you already have.
Cheers Tim
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Well stated. And don't even get me started on "mic shootouts"!
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The mic is just one factor. The cable, mic preamp and conversion can have an equal amount of sonic influence. Post processing, compression, EQ, etc. makes it even more unlikely anyone can ever guess what was used with any certainty. After a year or so, I can't remember what I used either, if anyone ever asked.
I can think of about a dozen or two mics that could be used, no idea on compression, EQ, autotune, etc. No, no guesses from me!
I do find frequency plots helpful. Polar plots are even more helpful. Better to have some information than none. You can get a general idea what you will get looking at one, especially if it's done individually for that one mic. Like a score or a schematic, you do need to know how to read them.
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Jim,
It's funny that you should mention the cable. I have thought about this a bit lately-- It's something to which I seldom if ever pay attention. I do know from experience that low-level instrument cable runs can vary sonically from make to make (and certainly from length to length). I've always considered it possible that the same could be true for line-level balanced runs, but I haven't experimented much.
You place it here in a list with microphone, preamp, and conversion. I'd always assumed its importance would be much further down-list from these parts of the chain. Is that a flawed assumption, in your opinion?
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Brad,
Jim hasnt chimed in yet although I'm sure he will.
Here's a quick response FWIW:
If we start with a good quality balanced cable, fed by a good 150 ohm mic its influence on the sound will be negligible on short runs. Beyond some cable length it will start to have an influence, first as a slight loss at the highest frequency we are considering, say 20khz.
But I think the effect of the cable length can be easily overstated. On typical runs back to a mixer at the back of a medium sized venue I would have thought it was pretty negligible and other factors such as mic placement and use, would have a far greater impact.
Unless these losses can actually be quantified, in this case as a loss in db at a certain frequency, per a certain length of cable, it can all get a bit wooly, and misunderstandings can abound. Again, it has to be quantified. That puts it in some sort of perspective.
For me, if I was mixing sound at a live gig and the length of mic cable was creating a loss of 1db at 20khz, it would not bother me in the slightest, at least not to the point of feeling the need to install low output impedance distribution amps back to the mixer!
Cheers Tim
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Unless these losses can actually be quantified, in this case as a loss in db at a certain frequency, per a certain length of cable, it can all get a bit wooly, and misunderstandings can abound. Again, it has to be quantified. That puts it in some sort of perspective.
See, measurable quantifiability is not that important to me-- only repeatable perceptual differences (as in "I can consistently hear and confirm a preference for one or another.")
I'm OK with things getting a bit nebulous and unquantified and "wooly." To me it's not important that I measure a difference, only that I can hear one-- and my personal experience leads me to feel that the two are not necessarily intuitively correlated (or, more to the point, we don't always know to measure for the right thing!) Again, (relating squarely to the more central thrust of this thread), measurable frequency response is only ONE part of the story-- and what happens in one system may change when employed in another system (with different impedances for source and load, etc)*.
To quote my friend and colleague Allen Farmelo, a big part of what we do constitutes "skating on the thin ice above Lake Placebo." We're often dealing with very fine grades of perception here, and that's OK. Sometimes you only feel a wisp or hint of a difference, or preference... on another day it may not be there, or you may have the opposite preference. Some preferences are only built up or understood over time, with context and experience. This is all OK with me and doesn't drive me up the wall... it's all just a part of those tiny improvements that (hopefully) add up in aggregate to a superior result.
People have different styles. Some are really unsettled by the notion of accepting something that cannot be proven with non-listening test results. I'm more of the camp that the best methodology for determining how something sounds is to listen to it.
* this is actually another thing we really should bring up here regarding the marginal (at best) utility of documentation purporting to show a microphone's performance. If a microphone has, say, a 50 ohm output impedance but we amplify it with a preamp expecting to see a 600 ohm input, it can change the performance rather noticeably... ringing/overshoot, changes in frequency response, etc.
Certain microphones are more sensitive to this than others... older RCA ribbons can have dramatic changes in high-frequency extension depending on the input impedance of whatever you're amping them with.
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Cable differences can usually be heard here only because anything that could mask those differences has been already corrected/optimized. It is the last step after everything else is exhausted. I wouldn't bother unless you have done everything else to the system first.
Being said, anyone can do these 'tests'. I use either Ray Kimber's excellent stuff or I use military silver/teflon braids or low capacitance LAN cable like Belden 9182.
Set up a fast, clear condenser mic and get a 20 foot run of Ray Kimber's AGSS pure silver/teflon 3 braid. Swap to any other 20 ft. cable, it's very easy to hear the differences. At $80 per foot, you ought to. Steady-state signals from analyzers don't replicate the violent dynamics of real music. This is why that Kimber wire may not measure any differently in the audio band than a common XLR cable. Run it through a 100 mhz network analyzer and the differences start to show up.
Most will never experience this level of resolution, the admission price keeps the masses out of that venue. For many musicians, it will expose too many mistakes and may not gain favor with them.
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See, measurable quantifiability is not that important to me-- only repeatable perceptual differences (as in "I can consistently hear and confirm a preference for one or another.")
To me the two go hand in had, and are not opposed to one another.
These days I cant hear anything above about 11khz. Should I ignore what the measuring instruments are telling me about what is going on above 11khz just because I cant personally hear it? I suggest I would be a fool to ignore it.
Cheers Tim
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If we start with a good quality balanced cable, fed by a good 150 ohm mic its influence on the sound will be negligible on short runs.
Says who? My experience has taught me otherwise. There are significant enough differences between cables, that I throw in the type and length of cable I use for my work with all of my mods, so that I have some control over combination and the end result.
Unless these losses can actually be quantified... it can all get a bit wooly, and misunderstandings can abound. Again, it has to be quantified.
To this day, hard science has been unable to quantify some the most important parameters in audio, due to the complexity of scientifically analyzing how a sensory perception comes about and how its nerve signals are to be interpreted (the ears are the transmitters here, like the nose is for olfactory sensations, the palate for gustatory, etc. ) You can call it "wooly", but it's unrealistic, and, for the sake of good audio, entirely unproductive to discard a whole category of experiences, only because our microscopes are not good enough to "quantify" them and establish a easy link to causality.
Think of psychiatry as an example: no bio markers have ever been conclusively linked to any psychological diagnosis; yet, we readily accept that some people suffer from PTSD, schizophrenia, etc...
I find this endless discussion about "can't measure (cable, capsule, tube, amp, etc.) differences, therefore none exist" tiring, and am personally done with it, certainly on my forum. Believe what you wish, but, as with religion, it would be best to respect those who don't share yours, and leave it at that.
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See, measurable quantifiability is not that important to me-- only repeatable perceptual differences
That is a logical concept if you only mix for yourself. For those with greater sensory perceptions, that is sonic robbery.
Sort of like raving about the latest deaf musician or blind artist.
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Jim,
Point noted. I should have phrased it differently, I suppose.
In cases where I can hear a difference between two things, I'm not overly concerned with which "measures" better, only that which sounds nicer to me. In those cases where I can't hear a difference, there's no harm in going with the one that ticks all the boxes from an objective standpoint, I guess.
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If your hearing bandwidth is 11k hz, I would use another person to gut check the tracks for me. It's no different than using another set of eyes to see the details your tired eyes miss.
Got a kid?
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If your hearing bandwidth is 11k hz, I would use another person to gut check the tracks for me. It's no different than using another set of eyes to see the details your tired eyes miss.
Got a kid?
Last time I aligned a tape machine (about 2 weeks ago), I still had at least 16k (thank heavens). Tim was the one who stated he didn't have much above 11k.
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If your hearing bandwidth is 11k hz, I would use another person to gut check the tracks for me. It's no different than using another set of eyes to see the details your tired eyes miss.
Got a kid?
Exactly. That was my point. I used the example of an FFT spectrum tool as an aid but a kid with great hearing is also a useful aid.
Now who else is going to give their ears the same unbiased check I've been giving mine for years, and submit the objective results to this forum column? Dont all speak at once now! ;)
Tim
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Last time I aligned a tape machine (about 2 weeks ago), I still had at least 16k (thank heavens). Tim was the one who stated he didn't have much above 11k.
I've aligned a lot of tape machines over the years and it was in the course of doing that work regularly that I discovered the upper limits of my hearing.
But I assume that your reason for being thankful about still being able to hear 16khz is not primarily for its helpfulness in aligning a tape machine. In any case that task should be done using calibrated instruments which can respond to signals with quantifiable accuracy - in terms of level, frequency, distortion, far better than any human ear can judge.
Still I'd always do a final A/B listening test between source and tape playback as confimation that the instruments were doing their job, which they nearly always did.
The point I was making earlier on was just this, that in the end there is no conflict between the measuring instruments and listening tests. It's when people try and place the "science" and the "listening" in opposition to each other that the problems start, I'd suggest.
Which brings us full circle to the reason I started the thread. There seems a strong view abroad that since "every human voice sounds different" which is undoubtedly true, therefore we need different microphones to capture those different voices. I dont see the documented evidence that that is true but I'm more than happy to be shown it.
Tim
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Now who else is going to give their ears the same unbiased check I've been giving mine for years, and submit the objective results to this forum column? Dont all speak at once now! ;)
Tim
I went to an audiologist last year to get checked. Turns out I have very good hearing for my age. The results showed minimal loss in the left ear (road noise) and nearly perfect hearing in the right ear.
She commented that it was very unusual to test someone at my age with those great results. She also said that most teens now test with severe hearing loss, mostly due to loud enviromental noises and those dreaded 'ear buds'. Only small children still test well. That will end with their first 'ear buds', the quickest way to damage your ears, permanently. I don't have kids, but if I did, those would be off-limits until they turned 18. Any parent that provides those to their kids is sentencing them to permanent hearing loss. You might as well give them acid eyedrops for their eyes too.
I'm not one that was sheltered from loud sounds. I grew up playing rock music, but at an early age I decided ear protection was needed. That began in 1978. After several tours with Stevie Wonder, they became a part of life and where carried everywhere.
Now I'm in my 60's and still enjoy playing on "11", but with ear plugs always used. Same for shooting sports, no hearing loses from that either. ( I use suppressors and stuff there too).
Unfortunatly, these protectionist concepts tend to come later in life, usually after damage has occured. Smart kids are pro-active, as I was at an early age. That is not the norm as most kids don't think about this stuff until it's too late. We now know what hearing damage can do, same with sun exposure and tobacco use. Teaching the kids to be aware is 1/2 the battle.
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On a gig when I was 21, a drummer was really laying into a crash cymbal. I had earplugs with me, but had forgotten to put them in. That's the only time I felt physical pain, and it was in my left ear. I reached for my earplugs and they fell behind my amplifier.
It still felt weird when I woke up the next morning. Right then and there I decided that such a thing would never happen again, and I became very protective of my hearing. I have custom ear molds from Westone, and I wear them walking around the city. Subways and worn-out brakes on taxicabs and buses make incredible levels of noise. I wear them when I run the vacuum cleaner, and even if I have to use a hair dryer. I make my living mostly as a session guitarist, and I like to wear the custom plugs underneath my tracking cans, just in case the sound in the room tempts me to turn my cans up louder than is wise. There are so many potentially damaging environments that we don't ever pay attention to.
I'm not sure that any permanent damage was sustained in my left ear that night, but I can almost guarantee that the wake-up call I received has saved me from lots of damage.
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Interesting comments Jim and Brad. This has turned into a thread on hearing loss and protection but that's fine by me.
When I was 25 I started work in the hearing aids industry. It was a good education to see of these people, often retired farmers with many tractor driving hours to blame for their hearing loss. It's not just the volume but the "dose". The longer the exposure at a certain level, the more damage.
Like Brad I've been using ear protection for years whenever I use the vac or any loud equipment such as a noisy air compressor, or when banging metals, using a hammer drill, tuning a car motor. etc.
I think there can be a psychological component here as well. I once played in a band with a guy who liked the foldback really loud, especially on his own vocals. As we shared the same foldback speaker it created a problem. I found the voulme ear splittingly loud and often ended up playing the gig way off axis from the speaker just to protect my ears. I concluded that for some, loud music is a sort of drug which excites them.
Also that different people seem to have different thresholds for discomfort and pain in their hearing. Mine has been fairly low.
The other thing not always appreciated by music and audiophile types is that our ears are sensitised to frequencies in the "presence" range, say 1khz to 6khz, and so that is the band that tends to be lost first, as it's easily overloaded. Many clients I dealt with in hearing care had acceptable thresholds at 1khz but a steep dive in response above that, especially around 2 to 4khz. It would often somewhat recover around 8khz and perhaps above that.
This band is critical to clear understanding of speech and of the ability to function in daily life. Someone who struggles to hear well around 2 to 4 khz has real problems. In that sense, a loss of highs say above 4 or 6khz is not nearly so critical. We often didnt test people above 8khz, for if there were sharp losses around 2 to 4khz there was not much point testing above that for we had located the real problems for their hearing in daily life.
Tim
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I just read this thread and want to comment. I am a microphone designer.
We do measure frequency response on every individual mic, particularly in the tuning process.
On axis response of course won't tell everything about the sound of a mic, but it's important data.
It should be carefully and tightly controlled in the manufacturing.
Do published responses mean anything? Well we electroacousticians have a joke about that....
"drawn by the marketing manager". In many cases that's not far from the truth.
A real frequency response chart will have many small sharp wiggles from mic stand or body reflections
unless steps are taken to reduce them. Many lower cost microphones have huge sharp 5-10 dB peaks
and notches in the mid and upper range. Some expensive ones too. And you can sure hear it. This might be a good thing depending...but in general a microphone is not a minimum phase network, so they can't really be eq'ed out. I tend to not like the sound of very sharp peaks or dips on many things.
Is there any standard method? Yes, a single free field plane wave. There are some problems doing this at very low
frequencies with gradient microphones, and much data has significant errors in it. The best way was and is a plane wave tube. For pressure microphones LF measurements can be done accurately in a small pressure chamber.
Can we isolate capsule distortion? Yes , in a limited fashion. Extrapolating from two speaker intermodulation is one way. With gradient mics the bigger issue is getting the tremendous SPL in a free field. The usual method
is powerful compression drivers feeding a resonant tube with multiple resonant absorbers tuned to harmonics.
At very high SPL the air itself creates harmonic distortion however.
Other thing that strongly affect the sound? Off axis response with multiple sources and room sound.
And distortion, which can be quite large in shunt or stray capacitance loaded constant charge condensers.
Many head amps produce large distortions (on purpose).
One thing i'll add...yes our super flat low distortion B&K/dpa reference mics sound horrible in the studio!
Les
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A fitting summation of this discussion. Thank you.
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I just read this thread and want to comment. I am a microphone designer.
We do measure frequency response on every individual mic, particularly in the tuning process.
On axis response of course won't tell everything about the sound of a mic, but it's important data.
It should be carefully and tightly controlled in the manufacturing.
Do published responses mean anything? Well we electroacousticians have a joke about that....
"drawn by the marketing manager". In many cases that's not far from the truth.
A real frequency response chart will have many small sharp wiggles from mic stand or body reflections
unless steps are taken to reduce them. Many lower cost microphones have huge sharp 5-10 dB peaks
and notches in the mid and upper range. Some expensive ones too. And you can sure hear it. This might be a good thing depending...but in general a microphone is not a minimum phase network, so they can't really be eq'ed out. I tend to not like the sound of very sharp peaks or dips on many things.
Is there any standard method? Yes, a single free field plane wave. There are some problems doing this at very low
frequencies with gradient microphones, and much data has significant errors in it. The best way was and is a plane wave tube. For pressure microphones LF measurements can be done accurately in a small pressure chamber.
Can we isolate capsule distortion? Yes , in a limited fashion. Extrapolating from two speaker intermodulation is one way. With gradient mics the bigger issue is getting the tremendous SPL in a free field. The usual method
is powerful compression drivers feeding a resonant tube with multiple resonant absorbers tuned to harmonics.
At very high SPL the air itself creates harmonic distortion however.
Other thing that strongly affect the sound? Off axis response with multiple sources and room sound.
And distortion, which can be quite large in shunt or stray capacitance loaded constant charge condensers.
Many head amps produce large distortions (on purpose).
One thing i'll add...yes our super flat low distortion B&K/dpa reference mics sound horrible in the studio!
Les
Thanks for your comments Les. Obviously mic stand or body reflections are independent of the mic itself and so would hardly be a reason to change to a different mic when recording.
In the same way, bad peaks and troughs in response in a cheap and nasty mic are also not what I was talking about.
Can you supply examples of a few typical good quality mics' response curves. Not the ones "drawn by the marketing manager" but the actual empirical responses with all the sharp peaks and troughs intact?
Do you also have a view on why as you say the B&K/DPA mics sound so terrible in the studio?
Cheers Tim
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If you saw an un-edited mic response curve you probably wouldn't buy it. It looks like an audio waveform on an editor. Hundreds of spikes and troughs, no resemblence to any frequency curve you've ever seen. Most would have a tough time even finding the base line!
As I said before, the published curves are "normalized", like stretching a hose straight. Run enough passes and any wild, spiky looking curve can be "pulled straight". Is it honest? Your call. I don't find it any less misleading than any modern audio piece that's sold without any specs. Once I saw a Royer ad with a hand drawn curve and hand drawn frequency breaks, none of which resembled a log frequency curve, it was "made up" out of whole cloth. Didn't stop folks from buying them.
"Trust, but verify" No truer words were ever spoken. That's why I have the Audio Precision analyzer here.
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Run enough passes and any wild, spiky looking curve can be "pulled straight".
Jim, what do you mean by this? Are you saying that each pass gives a significantly different result to the one before? That could only implicate the testing procedure rather than the mic itself.
If so, "running enough passes" and averaged them out would seem a valid way of getting a more accurate plot. If not, what did you mean here?
Tim
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An un-edited mic response curve is very spikey. Normalization software programs are used to "smooth out" that result. In my Audio Precision, it's called "compute smooth".
You can take any frequency reponse plot and apply that program. It can also be applied to any graphic plot on that system. Usually it's done to speaker and mic response curves. It makes the curve more "readable" but covers up a bunch of variations. Marketing folks love it as it takes away worrysome test results and makes it all pretty for the sales team.
The number of passes determines how "smooth" the end result becomes. The software is averaging the data and is "filling in the holes", so to speak. Passes means how many times you re-use the compute smooth function, not how many "tests" you sweep the mic with, that is done only once, then the computer takes over.
An honest plot would show before and after results, but most would not know how to interpret them or they might be scared off from those truthful results. Would you buy a mic that looked like a picket fence on a response sweep?
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An honest plot would show before and after results, but most would not know how to interpret them or they might be scared off from those truthful results. Would you buy a mic that looked like a picket fence on a response sweep?
On the one hand Jim, you seem to be condemning the "smoothing" practice, and on the other, almost justifying it. I'm confused.
As I said earlier, I would like to see that " honest plot" if as you imply the ones we are given are dishonest.
Tim
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It's been pointed out: the "honest plot", if it even exists, does not get published by manufacturers because it serves no purpose, other than maybe aiding in mic development to remove kinks.
I have never seen a graphs that were more detailed than those Sennheiser used to include with their mics. And even these were already so detailed that an untrained customer would only be tempted to overanalyze their jagged trace.
In summation of this thread, I think we can agree that, short of being useful during the research and development process, frequency plots are not helpful as indicators for the real-world performance of a mic.
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I take it that the "honest plot" is the real world performance of the mic, with respect to frequency response, much more so than the smoothed plot. Are you now saying that it isnt?
If so, of what use would such a plot be even to designers? I take it designers design their mics for the real world.
Tim
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I take it that the "honest plot" is the real world performance of the mic, with respect to frequency response, much more so than the smoothed plot. Are you now saying that it isnt?
I think what we're saying here is that the "honest plot" is representational of the "real world" performance of not just the mic, but other variables as well (that can be hard to control for).
Variations/imperfections in the test chamber, the test setup, reflections of the mic stand in the test chamber, and perhaps some other uncontrolled (or uncontrollable) variables.
In the end as Klaus said-- no chart or graph will tell you what you need to know in order to select the best microphone for a given application or source. You must rely upon your ears and experience for that-- there really is no better way.
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On the one hand Jim, you seem to be condemning the "smoothing" practice, and on the other, almost justifying it. I'm confused.
As I said earlier, I would like to see that " honest plot" if as you imply the ones we are given are dishonest.
Tim
It's a tool. It has a function and is useful. Can it be misused? Yes, like any tool. I try not to do that sort of stuff here.
I find mic response curves helpful. Seeing a mic response with a big bump at 5k hz tells me it won't sound like a mic with a flatter response. Will it tell me what it sounds like? No. At least it's something.
Trust, but verify.
Listen to it after reading the plots. It's how I've always approached microphones. Take in all the info you can, it helps make for a more informed decision.
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...what use would such a plot be even to designers? I take it designers design their mics for the real world.
For example, head basket construction could be optimized with the help of detailed frequency analysis, to show where certain frequencies are concentrated, due to standing waves from reflections. Response could then be improved by measuring and adjusting the distances correlating to the wavelength of boost or cut.
But it's a fairly safe guess that in the "real world" no one ever goes that far, because
1. the parameters of good mic design have been mostly established by now, and
2. you can get there with good ears just as fast or faster (that's how, for example, the Brauner KHE's head basket weave and pattern was arrived at)
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What we are discussing here is only the backdrop to the other assertion I read these days about "matching" a mic to a particular voice. It is that which I question and its validity.
Sinatra and the U47 is often mentioned as an example. Reading some people today you would get the impression that back then in the 40's/50's they tried different mics on Sinatra's voice and finally came up with the U47 as the best match.
But when I read it from the guys who were actually there, there seems no such suggestion. They speak of having used RCA ribbon mics up until that point, not only on Sinatra's voice but lots of other instruments as well. It was just the best mic they had at that time. Then when the U47 came along they used that on the instruments and also on Sinatra's vocal because it was flatter with a better top end than the RCA ribbon. So it was used on the horns, the guitars, the strings etc as well as on Sinatra's voice. The implication was that yes it suited Sinatra's voice better but that it suited the instruments better and indeed any voices better. It was just a flatter more capable mic!
Many people fall in love with a particular vocal recording and their first question so often is "what mic did they use on xxxxxx's voice?" The artistic and the technical get all confused.
If it's true that one particular mic is subjectively the "best fit" for a particular vocalist, even down to singing in a given key signature, then ten top engineers/producers should independently of one another's choices, arrrive at exactly the same mic choice.
But as far as I am aware, it's never been tested. The idea seems to have been accepted as Gospel, as "fact" without ever being checked. That's what I am saying.
Tim
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Choosing the right mic for the right voice/instrument is an artistic decision that defies scientific evaluation.
You keep insisting that somehow science has a grip on that, and if it cannot be scientifically demonstrated what engineers and artists and producers hear, it's not valid. In my opinion, you overestimate the reach of scientific investigation into audio. It's still in its infancy, and limited to rather raw and course datapoints which are not even remotely capable of capturing our hearing.
It's been a long and moderately informative thread, and I will now close the kitchen on this subject.