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[Kai]

..using a microphone with artificially boosted top end, or using EQ ahead of the tape machine, would have been a strange way to address the problem of a poorly  maintained machine.

Even with perfectly aligned machines (this was the normal situation!), in the analog era boosting the treble before going to tape was very common and necessary. You either had a machine without Dolby, then you had to watch out for the signal to noise ratio, or you had the Dolby's which had negative influence on the attacks and therefore on the subjective treble dynamics.
Usually you recorded very hot, and this further compressed the treble by saturation. When I switched to digital (32 track PD-format) this was the biggest change for me, I could define the amount of treble in the mix.

[klaus]

Agreed, I phrased that sentence poorly.

I should have said:

"Cumulative masking and other tape noise when you combined 48 individual tracks affected overall high-end and its subsequent treatment during mix-down. One way to mitigate the problem up front, (though poorly) was by boosting high frequencies in microphones".

I cannot tell you how often I was forced to boost beyond my own comfort range, just to make people happy.

P.S.: This discussion is of course WAY off the original U67 thread, but I'll leave it be. Once I have the U67 reissue in hand, I'll start a fresh thread on just that subject.

[Timtape]

Even with perfectly aligned machines (this was the normal situation!), in the analog era boosting the treble before going to tape was very common and necessary.

Perhaps perfectly maintained and aligned machines were common in studios which could afford it and exercised due diligence but I'm not sure it was the normal situation across the board, from the big studios down to very small outfits. (I serviced tape machines for smaller outfits and often I couldnt believe how badly maintained and aligned they were).

Boosting the treble (and cutting it by the same amount on playback!) was useful in recording some instruments not strong in treble content, such as a naturally dark sounding piano. You were lifting what quiet treble sound was there in the performance above the tape noise, but without unduly driving the tape into saturation. 

You either had a machine without Dolby, then you had to watch out for the signal to noise ratio,

Of course and it depended on the programme being recorded, classical music being generally the most demanding, and on the S/N of the tape machine and tape, eg: wide or narrow tape tracks, older or newer tape formulations. And it wasnt just the treble. The dynamic range of pro machines was not brilliant across the whole spectrum, but it was much more even than say cassettes where the S/N in the treble spectrum was much worse than in its mids and bass.

 or you had the Dolby's which had negative influence on the attacks and therefore on the subjective treble dynamics.

Ray Dolby's A system, unlike the later economical Dolby B for cassettes, was a full range system, improving the S/N from the lowest bass to the highest treble. If the noise was only an issue in the treble, Dolby's job would have been a lot easier and the processors studios bought would have been a lot simpler and cheaper.

Did Dolby A mess up the treble? As far as I know, well designed and maintained Dolby A circuitry itself was essentially transparent  (easy to test this: connect the encoder's output to the decoder's input - no tape machine in circuit - and listen for any distortions) but when used with a poorly aligned/ maintained tape machine, Dolby A did exaggerate any misalignment. Even momentary tape dropout was exaggerated. All  double ended NR systems required very high standards of machine maintenance and calibration, with some more fussy than others. No surprise as they were compansion systems.

Usually you recorded very hot, and this further compressed the treble by saturation.

Recording very hot tended to compress/distort whatever portion of the spectrum was saturating,  whether bass, mid or treble, as well as caused IM distortion, which sort of defeated the purpose.

Of course greatly compounding the problem was generational losses. Particularly so in film production. Cinema audiences could be hearing a sound track 5 generations removed from the original elements.

When I switched to digital (32 track PD-format) this was the biggest change for me, I could define the amount of treble in the mix.

Yes and nearly everybody uses digital today for good reason.

Klaus mentioned people wanting mics with a large treble boost, apparently as a general fix to compensate for poor S/N in a tape machine.  I suggest these people were not well informed in that it didnt really solve the problem and was a fairly primitive technique at best.

Regards,
Tim
 

[Nob Turner]

I know, I'm responsible for this bunny trail off the original thread. Still, I'd like to repeat that everything, back in the day, went through at least 2 analog generations: multitrack and mixdown. If you were comping and/or flying parts, there were more. Each added noise and nonlinearity (the latter in the top and bottom end in particular). Yes, in theory analog machines were flat. In practice, they never were.

I also had the experience of the sound coming off tape "relaxing" after a day or so on the reel. I have no scientific evidence to support it, but I often noticed that what I'd recorded on one day typically sounded a bit "gauzier" the next. Yes, the machines were de-gaussed daily. Yes, they were aligned, maintained, etc. So, like many, I developed the habit of boosting high end on the way in, so that I'd actually have more or less what I wanted later on. Not to mention not wanting to have to boost too much top end when the tape's inherent noise had been added to the original signal.

With the advent of digital recording, I was able to expect a closer copy of what went into the recorder on the way back out. I'm not interested in arguing preferences for analog vs. digital; I'm just saying that my work just changed significantly when the medium changed. In particular, my choices of microphones were different as I adjusted.

[Timtape]

Thinking about the loss of treble it sounds like gradual demagnetisation due to repeated shuttling the tape back and forth to do overdubs. The treble is the first thing to go. I think Roger Nichols describes this happening very badly in a Steely Dan session.

[Kai]

I know, I'm responsible for this bunny trail off the original thread.

Don't worry, it's fun to remember the old days and it has a lot to do with how mic's were tuned at that time.

I also had the experience of the sound coming off tape "relaxing" after a day or so on the reel. I have no scientific evidence to support it, but I often noticed that what I'd recorded on one day typically sounded a bit "gauzier" the next.

It's not from one day to another, but the tape beeing played multiple times during overdub an mix degraded the sound. Something I noticed very often.
This negative effect was enhanced by the Dolby systems.
As I did my machine maintainance by myself I ended up precompensating this by adjusting the machine's treble a tiny bit on the bright side ([email protected]) and the level very slightly on the plus side too.
This even compensated for tape saturation effects and made the Dolby act subjectively more linear.

IM distortion BTW wasn't that much of a problem, as the split into a multitude of channels prevented much of the frequencies interaction.
What was left was the dynamic harmonic enrichment and the "limiting" effect of tape saturation, being positive or negative depending on the source.

Finally, in the context of microphones, the today so famous great oldies were build to work best with these systems, long before digital recording.

[Timtape]

Is there any documented evidence from the microphone manufacturers themselves that they designed mics with built in treble boost to compensate for tape demagnetisation? I've never read anything like that.

It always made sense to me to compensate for a tape machine problem at the tape machine. Kai mentions setting up a tape machine with slightly bright treble to anticipate mild demagnetisation. There's good support for that practice in some  tape machine service manuals where a specification for  10kHz re 1kHz would have a tolerance of say (0 to +1db), especially when Dolby NR was engaged.

[Kai]

Is there any documented evidence from the microphone manufacturers themselves that they designed mics with built in treble boost to compensate for tape demagnetisation? I've never read anything like that.

Of course not, but everything sounded a bit softer in those days; remember the all-tube preamps and mixers we had.

Then came germanium electronics, still soft; silicone, with the tendency into harsh, mainly because engineers did not know how to use it; soon after that the first generation of operational amplifiers (the 741), very slow and therefore dull and distorted sounding.

Not to mention the media with which the music was delivered to the customer: vinyl, compact- and 8-track cassettes, all with their own sound.

And then, from this deep valley of really bad sound the quality emerged into what we have today.
All this had influence on the way microphones were built and tuned, as it was and is the end result that counts.

[Jim Williams]

Tape sound was a lot better than some recall. Not everything was a mush machine. Back in the 1980's high test analog machines were used. In 1980 Stevie Wonder got one of the first digital 3M machines. "Hotter Than July" was recorded on it with an API console (another mush machine).

I routinely rebuilt analog machines in the LA area back then. Some would drop THD levels from the stock .55% at +3 down to .15% at +9. The frequency response on some 1/2" mastering decks would reach 32k hz. Back then the decision was to either use the DAT mix or the 1/2" at 30 IPS. The 30 IPS won every time.

[Timtape]

...All this had influence on the way microphones were built and tuned, as it was and is the end result that counts.

Again do you have any evidence for that?

[klaus]

There is a place for evidence-based discussions in audio forums, but you seem to over-reach with your repeated requests for iron-clad, objective outcomes in a field that does not easily produce the type of scientific proof you want.

May I remind you that observation and sensual impressions are also part of scientific exploration? Your education about microphones may indeed benefit from observing the deep level of experience veterans in our field share here.

No one stops you from venturing on your own into examinations and the type of scientific inquiry you have in mind, and I'd love it if you would share those with us.

[Kai]

Again do you have any evidence for that?

Yes, I have as I have been involved in audio developments of all kinds for a long time. It's always an interaction between trying out something, listen to it, measure it, test it in the real world and with your potential customers and then change it until everyone involved is satisfied.
This does not mean I have insight how Neumann developed their microphones in 1950, because I was not born at that time, but I guess it wasn't much different.
I bet that they did a lot of listening and other practical evaluations (including recording), because the possibility for measurements was much more limited, and they had years of development for every model, and a high commercial pressure doing it right.

[Timtape]

Sure that sounds fine but in the previous post you seemed to suggest mic manufacturers changed the design or performance of their studio mics on the basis of the active electronic components of the day in amps and pre's  like tubes, germanium or silicon transistors etc. Or on the basis of whether the music recordings were released on vinyl, cassette or 8 track etc.
It's true mastering engineers took  care to optimise  the recorded signal as it was  cut for vinyl, and perhaps to a lesser extent for cassette and 8 track.
It's also true that at mixing stage, staff listened to mixes on smaller low fidelity speakers like Auratones to help gauge if a mix still sounded reasonable on limited fidelity consumer systems.
But the idea that studio microphone parameters were altered on the basis of such factors further downstream of the recording, or even downstream of the microphone is something I dont remember ever encountering before.

Regards
Tim

[Kai]

But the idea that studio microphone parameters were altered on the basis of such factors further downstream of the recording, or even downstream of the microphone is something I dont remember ever encountering before.

Think of the sound change from Neumann's M7 capsule to its successor, the K47, and correlate it with the sound evolution of the typical audio chain of the regarding time. I can see some coincidence.

Do you think this difference happened just by chance or wouldn't an advanced company like Neumann have done this on purpose?

I admit I'm fishing in muddy waters, but... nothing comes from nothing they say.
You can even turn that around -  if the sound of a microphone wouldn't have fit to the contemporary taste and circumstances it would not have been a commercial success and we would not know about it today.

If we look further we can see, with the appearance of high samplerate recording systems, microphone manufacturers started to build microphones with defined frequency responses beyond 20 kHz, e.g. if you go to the Schoeps website the "Schoeps CMC 6xt U".

[Timtape]

I'm sorry Kai but I am struggling to understand what you are talking about here. I'm not sure what more to say.

Best wishes
Tim