Track Fader Position and Coloration

[MJP]

I have a client who swears he's hearing coloration when I sum 3 tracks via a bus to an aux input and send that to the mix bus. The 3 tracks' outputs were set to none. Eventually I'll group these tracks and use a VCA, but I was working quickly and found it easier for what I was trying to accomplish.

Am I missing something? He claimed that things sound better when the track faders are set to 0 db and it's best to get them there using clip gain which on its face is reasonable I suppose, but in the scope of a large mix where every track is comprised of many clips, this can become very cumbersome to have to go back and adjust clip gains.

He mentioned that someone told him that fader resolution is best at 0 db. Is that True?

Pro Tools 2020.5, Apollo 16x16, IMac.

[albee1952]

While I tend to agree about the resolution being better around zero, that should not make a sonic difference. I would be more suspect that its a gain staging issue(maybe there is too much going thru the send bus and its causing some distortion/clipping).

[JFreak]

If there is any blind measurable difference, it is because something is driving some plugin crazy. Floating point mixer/plugins is great, but once you go over unity it begins to "smear" the sound so proper gain staging is still important.

One thing I specifically liked about TDM systems was the fixed point mixer/plugins. It would immediately notify with a harsh distortion when something went over anywhere. Fix it and keep going. No distortion, no problem.

With floating point the distortion is not always so obvious but it is still there. To oversimplify things, distortion of floating point mixer is the last bit, or mantissa (however mathematically fluent you are). It is the random nature of the last bit that makes things sound different from playback to playback, if your gain staging is not below unity.

As always, stay below the safety limits and only leave levels to the mastering engineer (or if you do it yourself do it in another session). Unless your converters have higher than 124dB dynamics there is zero reason to record anything hotter than -20dBFS and also if your DA converter does not cost many thousands you should not mix to the last bit (which means stay below -6dBFS).

There is a volume knob if you need to listen louder. Do not mess your mix with too hot levels.

[MJP]

I was using the aux input track to quickly group the 3 tracks in question. There were no plugins inserted to the aux track so there was no possibility of distorting. The meter on the aux track (if I remember correctly) was always at or below -10 db.

Since the client did not want to move the track faders away from 0 db so that these instruments as a group could be reduced in level, I wanted to quickly show the results by bringing down the aux track fader. Thus the use of the aux track.

As I said, the outputs of the 3 tracks were set to none (so making no contribution themselves to the mix bus) and these tracks were sending their clean unaffected signal to the aux input track. I realize this is an unconventional way to group tracks, but rather than taking the time to group them and use a VCA, I chose to do it this way as a test.

Thanks for the thoughtful responses JFreak and Albee. Albee, I know you're right about this. I believe the client mistakenly perceived what he believed to be some kind of coloration, and I just wanted to get some confirmation to what I believed that false assumption by the client was just that. A false perception.

[MJP]

Thanks Robruce! I wholeheartedly agree with your comment regarding keeping the client happy. In the end I'll do whatever is asked, but doing it in that way, I see a pretty time intense effort. It's a large project with many clips. The client, in an effort to get all track faders at unity, adjusted clip gains for every clip. I did not track the project and was hired to mix it. Before getting the requirement to keep all track faders at 0db, I had agreed to a price per song. This new requirement will definitely add time to the task. My only recourse is to either ask for more money or decline the work.

I will take a subset of one of the songs and do the test. when complete, I'll post back to this thread.

BTW, the hardware listed is not mine.

[sdemott]

In the days of analogue, faders had the best SNR at unity. But that is hardly relevant in a DAW.

The other aspect is that faders are logarithmic, which means they have finer control closer to Unity. But, that isn’t really going to affect the sound. It just means that the travel from Unity to +/- 6 covers less ground than an additional 6 dB of change. I wrote an article about this whole thing that’s on the Production Expert site. If I can find it I’ll post a link.

I’ll also add that hearing is the most psychological of the senses. We fool ourselves constantly. So you’re probably just stuck dealing with a client with somewhat unreasonable expectations based on non-scientific theories.


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[sdemott]

Ok I found those articles.

This first one outlines the reality of logarithmic faders & what that means:

https://www.pro-tools-expert.com/pro...-free-tutorial

But this 2nd article gets into the nitty gritty of it & hoes how a 1dB change is variable, depending on where the fader is:

https://www.pro-tools-expert.com/pro...nding-decibels


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