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Digital Faders: Gain Structuring
Old 8th November 2002
  #1
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Digital Faders: Gain Structuring

Hey Charles, just to let you know: I appreciate your taking the time and effort to answer all of our questions to the best of your ability. You're doing us a great service.

From the thread: "Mixing Technique 1: Getting A Concept For Your Mix" --

Logan

"I come from old school console mixing where I like all the faders up in the sweet spot and deal with levels coming in with the trim pot.... What is the statedgy for gain structuring these things."

Charles

"An answer to this topic is actually worthy of it's own thread (+ if more people would like to discuss this, let's start one), but I'll give a short and very controversial answer: (my opinion) This is digital not analog, so the question of a sweet spot doesn't apply (at least not in the same way—again hotly debated). My answer (only my opinion) is to just turn your faders down so you don't overdrive your stereo bus. (Again, let's please debate this in a "digital fader/gain structure/etc..." thread. Thanks.)"
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Ok, let's discuss digital fader management, and exactly how to avoid the dreaded red overs and still accomplish the best possible mix. This is important to me because I don't use the same method for every mix, and I'd like to simplify and improve digital gain staging. Whatever anyone can offer about how to handle digital levels will be much appreciated.

I tend to mix somewhat like Logan, and get everything sounding good with my fader balances first. Deciding which track will need to be heard above all others (usually vocals first), I begin with that track. If that first track needs any processing that will increase its level, I give it an estimated amount of headroom, based on what processing I think I'll treat it with. OTOH, if that track specifically needs reverb, I tend to raise the fader level, or leave it where it is, based on how much I estimate the reverb will soften its level. Prior to actually mixing, this is the process I follow, from the tracks that have the highest priority in the final mix on downwards.

Charles, your short answer is to pull down the faders to avoid overdriving the stereo bus. If you could elaborate on that a little: How do you differentiate lowering the track faders from lowering the stereo bus fader instead? Why would you choose to lower the track faders instead of just lowering the main stereo fader? I imagine the answer being that you have to treat the stereo bus as if it's the most important tool in the mix, and prepare the levels for it on your way there. But how do you prepare for that ahead of time? I guess you'd have to envision just how much room you'll maintain as you develop the mix.

Another solution is after you've achieved a balance that works, group all tracks except the main fader and pull them down until you have enough room to use the processing you want on the stereo fader. While that seems rather inelegant, it is a method I've used many a time.

I have read in other posts where you mention using many of the same plug-ins on each track from mix to mix. How does this apply to gain staging at the 2 mix? Do you have your normal set of processors applied so that they become intrinsic to the master fader's available headroom?

What am I missing?

Thanks!
Old 9th November 2002
  #2
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Curve Dominant's Avatar
Quote:
posted by Jax:
How do you differentiate lowering the track faders from lowering the stereo bus fader instead?
I'm suddenly interested in that subject as well, since I tend to keep the track faders hot, and lower the stereo master fader to avoid clipping there.

Not that I'm experiencing any problems in doing it this way - on the contrary. Just that this was an arbitrary (read: convenient) way of managing my mixes.

My mixes seem to sound hot from doing it this way. But I'm open to any suggestions as to why it may not be the best way.

I hope that makes sense...
Old 9th November 2002
  #3
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bassmac's Avatar
 

Lowering the track faders - prevents overloading the mix buss, and retains headroom.

Lowering the master fader - prevents the overall output from clipping, but doesn't reduce buss overload, or give you back any headroom.

A good goal is to manage your track faders well enough to prevent clipping of the master fader - while keeping it at unity. You can then bring up the overall output with your master fader plugs.

I think this gain strategy provides the best sound quality, and keeps Pro Tools the happiest.

Old 9th November 2002
  #4
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Quote:
Originally posted by bassmac
A good goal is to manage your track faders well enough to prevent clipping of the master fader - while keeping it at unity. You can then bring up the overall output with your master fader plugs.

I think this gain strategy provides the best sound quality, and keeps Pro Tools the happiest.
This approach significantly lowers the output of each track, thereby sacrificing a good amount of resolution. I have used this approach, as well as the opposite -- dropping the master fader as low as -22dB in some cases, with all final mix processing in place. I don't notice an improvement in sound quality either way. I think each method is equally destructive to the mix's sound.

Is there any consensus on what approach people think works best, and why? Are there other approaches not yet mentioned? Let's hear from some others as well!
Old 10th November 2002
  #5
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groundcontrol's Avatar
 

As mentioned somewhere else, don't forget that when you record a track, even if it only peaked at -24dBFs it would still be captured at 20 bit resolution. (What many so-called 24 bit converters are able to output as usable resolution anyway.) I feel it's better to record not so hot as to have to keep all the faders down too much and keep the master fader at unity.

Since I use a lot of analog outboard as inserts on my PT tracks anyway, I make it a point to try and keep a gain structure that's consistent and compatible with the analog world. (re.: 0VU (+4) = -18dBFs for dynamic stuff or -14 dBFs for more compressed stuff.)
Old 10th November 2002
  #6
Lives for gear
Just wanted to mention, that summing in HD has been improved in terms of overloading the INPUT to a summing bus. If you had 64 signals all at Full Scale ramming into the the same summing bus, the inputs still wont clip.

Peter
Old 12th November 2002
  #7
FX smörgåsbord user
 
Charles Dye's Avatar
 

Jax,

Thanks for reminding me to respond to this thread, I had meant to earlier. Sorry for taking so long.

”How do you differentiate lowering the track faders from lowering the stereo bus fader instead?”

I try to only adjust my stereo bus level by raising or lowering the individual fader’s levels. I prefer to only lower the master fader at the end of a mix (if necessary) and by never more than a few dB. Otherwise I will group all the faders directly feeding the stereo bus (with the obvious exception of all effect faders) + lower them until the stereo bus doesn’t clip.

”Why would you choose to lower the track faders instead of just lowering the main stereo fader? I imagine the answer being that you have to treat the stereo bus as if it’s the most important tool in the mix, and prepare the levels for it on your way there.”

I just think it makes more sense. My reasoning is that I think there is no point in pushing more level into the master bus just so I can lower the Master Fader to compensate for the clipping.

”But how do you prepare for that ahead of time? I guess you’d have to envision just how much room you’ll maintain as you develop the mix.”

Basically, yes. My approach is simple, but won’t work for everyone. (Depending on style of music + how you start your mix.) I use a technique similar to the one I use on analog consoles. I usually start with the kick + snare, and I’ve found that by allowing them both to peak on PT’s Master Fader’s meter @ about –14 dB (the first yellow LED on a ProControl or Control|24) that by the time I get to the end of the mix I will probably be peaking at right about –0.5 dB.

”I have read in other posts where you mention using many of the same plug-ins on each track from mix to mix. How does this apply to gain staging at the 2 mix? Do you have your normal set of processors applied so that they become intrinsic to the master fader’s available headroom?”

The only plug I have on the Master Fader while mixing is AC1. Never any other plugs. All the rest of the plugs I use on the stereo bus get inserted @ the end of the mix.

I hope this helps.
Old 15th November 2002
  #8
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John Sayers's Avatar
 

I know most of you are in PT but I asked this question on the nuendo site and the reply was "Don't worry, you have more headroom in Nuendo than you could ever want"

Just thought I'd mention it.

cheers
JOhn
Old 16th November 2002
  #9
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OUCH!
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