Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[hexfix93]

http://www.cadenzarecording.com/papers/Digitaldistortion.pdf

Which masters on here know about this and accomidate for it in their sessions? i noticed that once my buddy pointed me to the rme mettering stuff, once i isntalled it and looked at my mixes, i was like whoa.. i am getting overages, so now i turn my master fade down more to make sure it never happens..

but once you smash a mix to hell with a l2, or l3, you really get overages even though it says 0.3 on the meters max in wavelab, my rme meters say its going over... so yeah.. you should really check this out. you may not hear a difference on your dacs, but you will once its burned and you listen to it in a car or on your home stereo..

And nika aldrich's book "digital audio explained" to me is as good as bob katz's "mastering audio".. they are both teaching me a lot...

[Zilla]

hexfix93 wrote on Fri, 14 October 2005 13:30

.. i am getting overages, so now i turn my master fade down more to make sure it never happens..

This is a common gain-structure misconception.  Yes, turning down the master fader reduces the output of a buss, but the buss input may well still be in overload condition.  The way to achieve a more proper gain-structure would be to leave the master fader at unity and lower the channel faders.  By optimizing the gain structures of individual elements, you will free the whole signal path of unwanted overs/clipping.  This is true for both digital and analog scenarios.

[dave-G]

I'm not sure about other DAWs, but in Pro Tools HD (TDM systems), the master fader is not analogous to a master or buss fader on an analog console in the way Scott describes -- bringing down the master fader changes the coefficient used to to make the mixed ("summed") result..  It is mathematically and sonically identical to lowering all the individual faders that feed the master.

-dave G(reenberg)

[Zilla]

dave-G wrote on Fri, 14 October 2005 14:12

...in Pro Tools HD (TDM systems)...bringing down the master fader...is mathematically and sonically identical to lowering all the individual faders that feed the master.

I performed quick test and can confirm that lowering a MF in PT does appear to be mathematically equivalent to lowering the channel faders.  That is, it does avoid clipping.  Thanks for pointing that out, Dave.  However, I cannot confirm that it is sonically identical.  Somehow the effect of a MF's coefficient acting upon PT signals does leave some sonic fingerprint.  One I would prefer to be without, should I have an option (like removing the MF altogether and just lowering the channel faders).

So, I still say that applying basic, good gain-structure methodology will provide for a higher fidelity product.

[compasspnt]

At the risk of being repetitive, I will take this opportunity to say once again that recording from the first instance at lowered levels (speaking here only of the digital domain) will make everything sound better.  There is no need to go near the red, or even the yellow.  Don't even approach the problem area.

With analogue tape machines, of course, it's another kettle of fish.

[dave-G]

Zilla wrote on Fri, 14 October 2005 18:35

dave-G wrote on Fri, 14 October 2005 14:12 ...in Pro Tools HD (TDM systems)...bringing down the master fader...is mathematically and sonically identical to lowering all the individual faders that feed the master. I performed quick test and can confirm that lowering a MF in PT does appear to be mathematically equivalent to lowering the channel faders.  That is, it does avoid clipping.  Thanks for pointing that out, Dave.  However, I cannot confirm that it is sonically identical.  Somehow the effect of a MF's coefficient acting upon PT signals does leave some sonic fingerprint.  One I would prefer to be without, should I have an option (like removing the MF altogether and just lowering the channel faders). So, I still say that applying basic, good gain-structure methodology will provide for a higher fidelity product.

I completely agree on your last point, and Terry's.  

However, just to clarify... As it has been explained by people with far deeper knowledge than mine, the master fader is merely a GUI representation; If you deleted the master fader,  hit the "all" group and lowered all the individual faders, it is doing the exact same thing as lowering the master fader.  Either action creates the same "equation" (coefficients and all) in the mix engine.  If there is a sonic fingerprint, you'd get it either way.

The only point I try to make here is that there are far better things to worry about when it comes to gain staging and clipping.

-dave G(reenberg)

[chrisj]

You mean intersample peaks? If you're getting this it's because you're trying to be too hot and too bright at the same time. You can get bright, but there's a limit to how much you can cram into PCM audio.

You should also know that the guys doing your original request of going out to an analog chain and doing EQ and some of the gain boost before resampling are going to avoid this problem, because if you're not clobbering the signal with limiting AFTER resampling, a correctly designed ADC will already  eliminate slew angles that would cause intersample 'overs'. That's because that type of distortion is 'illegal' content for PCM audio.

Interestingly, you can take it and go to DSD quite happily with no problem from any combination of samples in PCM format, and I've been working on the problem of going from DSD to PCM and back (at least in theory- got no DSD authoring *snif*) But you can't take just any samples and put them on, say, a CD. As you've discovered.

...do I really need to add that I deal with this stuff when it comes up?

[hexfix93]

my theory is that the more you push or pull the recorded audio, the worse the sound becomes. and you will get more math errors by using the channel strip faders than just turning down the master fader..

honestly you should record in at the levels where you want the audio to sit in the mix, this way you will not loose sound quality as much... mixing while recording is your best bet for sound quality, but i think messing with the master fader will be less destructive to your sound that messing with each channel..

[zetterstroem]

so you think losing resolution in the A/D conversion wich is generally about 20bits S/N is better than adjusting a fader that has 32bits rsolution or more??

[hexfix93]

to my ears, yes... i've been working with cubase, and i think my mix sounds better when the mix is hot and i must turn down the master fader...

[Ronny]

hexfix93 wrote on Sat, 15 October 2005 07:22

to my ears, yes... i've been working with cubase, and i think my mix sounds better when the mix is hot and i must turn down the master fader...

When things are operating correctly in 32 float, there is no sonic difference between the mixer faders and the master fader. You can mix hot on the channels and attenuate the master, or put the master on zero and make sure the ch faders don't clip. The only place where you should hear any difference is when you are outputting the master section above -0dBFs. I don't do a lot of DAW mixing, but on digi consoles, I often have a fader or two above -0dBFs and as long as I attenuate the master section output by the amount that the ch faders are over, no problems. In a typical DAW, which digi consoles don't exhibit, is gain increase when summing multi-tracks. You can have all faders below -0dBFs, but "the sum" of the tracks places the input of the master section above -0dBFs, so "you must" attenuate the master fader. Either way, if things are operating correctly the system still reads the data as ones and zeros at either channel or master gain structures. The real important thing is, no matter where your final mix faders are at, you must not have the master section outputting above -0dBFs.

[bobkatz]

Ronny wrote on Sat, 15 October 2005 13:50

hexfix93 wrote on Sat, 15 October 2005 07:22 to my ears, yes... i've been working with cubase, and i think my mix sounds better when the mix is hot and i must turn down the master fader... When things are operating correctly in 32 float, there is no sonic difference between the mixer faders and the master fader.

Ronny is 100% right. So it would be interesting to examine how hexfix93 reached his conclusions...


BK

[Jack Schitt]

compasspnt wrote on Fri, 14 October 2005 19:31

At the risk of being repetitive, I will take this opportunity to say once again that recording from the first instance at lowered levels (speaking here only of the digital domain) will make everything sound better.  There is no need to go near the red, or even the yellow.  Don't even approach the problem area. With analogue tape machines, of course, it's another kettle of fish.

Is how far under 0db a platform dependant decision or is there a good rule of thumb in your mind where you like to see the peaks fall?

[masterhse]

Zilla wrote on Fri, 14 October 2005 18:35

However, I cannot confirm that it is sonically identical.  Somehow the effect of a MF's coefficient acting upon PT signals does leave some sonic fingerprint.  One I would prefer to be without, should I have an option (like removing the MF altogether and just lowering the channel faders).

Could this be due to some sort of quantization error? If it's truly mathematically equivalent how can it not sound the same?

[chrisj]

masterhse wrote on Sat, 15 October 2005 21:10

Could this be due to some sort of quantization error? If it's truly mathematically equivalent how can it not sound the same?

You'd have to be able to audit the code. A single bad variable that's int when it's supposed to be 32 bit float could do this. There's C programming errors that can do this, like doing math with constants not expressed as floats- divide by 3, get int output cast to float, divide by 3.0 and you're OK...

Anyway, rather than theorize on how it could sound different with the math the same, it might be a case of the math being broken.