I have a piece made up of various soft synths.  Each soft synth output is routed to a sub-mix bus, which then goes to the Master.  The reason for this is so that I can move the volume of the entire piece up or down with one fader without changing the Master fader, which stays always at 0.
 
I found that the overall level of the piece was quite low, peaking at -12db.    I'd like to have a stereo pre-master peaking at -3db.
To achive this I have various options, and I do not know which is the best choice, to give the best quality - if anyone can advise/suggest which of the following is the best choice (or something else) :
 
1.  Take the level of the sub-mix up over 0 ----( it can go actually only as far as +6db.   Question:  does going over 0 on this sub-mix cause any lowering of quality of the signal?)
 
2.  Go to each individual soft synth track and increase the levels so the overall level of the entire piece to master bus is higher.   This can be quite time-consuming with many tracks.
 
3.  Use a limiter on the sub-mix to increase the levels before it reaches the master bus (or a limiter on the master bus itself).
 
4.  Make the stereo pre-master at -12db, this is an OK level and can be increased with a limiter when mastering.

ULTRABRA
2.  Go to each individual soft synth track and increase the levels so the overall level of the entire piece to master bus is higher.   This can be quite time-consuming with many tracks.

 
You could save yourself some time and fader-fiddling hassle by quick-grouping the soft synths and then bringing all their levels up together.
 
As an alternative, you could tweak the input trim control on your synth mix bus.

In my opinion, -3dB is far too loud for a Pre mastered song.
 
Your -12dB is spot on the money and gives the Mastering guy plenty of room to work his magic.
 
In my opinion.

In your case, the intermediate bus is unnecessary. You could just as easily route everything to the master and make your final volume adjustments there. The result would be exactly the same.
 
Busses are normally called for in order to group your tracks so that you can do something collectively to a subset of them. For an electronic instrumental like you're describing it's probably not needed, but doesn't hurt anything. In digital audio you can run signal through any number of busses without degradation.
 
-12dB is, as Jonesey says, spot on the money if you'll be sending the mix out for mastering or even if you'll be mastering it yourself later. Only if you want to master it within the project yourself would you need to raise the level, in which case you'd apply a limiter to the master bus. Otherwise, a limiter is neither required nor warranted unless you want to use it as an effect.
 
The mix sounds quiet to you because you're comparing it to mastered material. If you're listening to it in the car or an iPod, just turn it up. You don't have to be concerned with loudness until you're ready to distribute the song on a CD or MP3. If you want to get a preview of what that'll sound like, put a limiter on the master bus and use it to bring the volume up closer to commercial levels. Later, when you're ready to send it out for mastering, simply bypass the limiter before exporting. The mastering engineer will thank you for the conservative -12dB mix.

bitflipper
In your case, the intermediate bus is unnecessary. You could just as easily route everything to the master and make your final volume adjustments there. The result would be exactly the same.

 
And quick grouping, as referenced earlier, will give the same "one fader to rule them all" functionality aspect of a bus.
 

The mix sounds quiet to you because you're comparing it to mastered material. If you're listening to it in the car or an iPod, just turn it up. You don't have to be concerned with loudness until you're ready to distribute the song on a CD or MP3. If you want to get a preview of what that'll sound like, put a limiter on the master bus and use it to bring the volume up closer to commercial levels. Later, when you're ready to send it out for mastering, simply bypass the limiter before exporting. The mastering engineer will thank you for the conservative -12dB mix.

Can we make that paragraph a sticky on every forum related to digital audio and recording?
 
(Well I can dream, can't I?)

Hello - here's a related Question:  Does clip gain add any distortion/modulation to audio, especially if you go up & down a few times?

I have always understood you do not want to lower the gain early in the gain stage, only to have to raise it later.  In other words, fix things early in the gain staging.
 
Bob Bone
 

Thanks for the input, really useful.
 
@bit:  Thanks for that comment about the Master - I always thought it best to keep Master at 0, but if the result is the same if I use a sub-master or Master for the overall levels, then obvouosly its much easier to use the Master (no setting up and routing all tracks to a sub-master).   So, as I understand it, I route all tracks to the Master, and adjust the level of everything by moving the Master fader, up or down so its either above or below 0 when exporting the final stereo wav.   
 
And re the -12db being an OK level - I wanted it higher not actually becuase it sounded better, I just thought it was better to add volume at the tracking stage, meaning I would need less limiting at the mastering stage (meaning:  I thought the quality of the final mastered version would be better if, for example I added 6db of overall volume + 3db of limiting, rather than 9db of limiting (just as an example)).
 
@ston: re the quick grouing, thanks for the tip.  That actually would work if I only had soft synth in a piece.   I do mainly, but sometimes there are some audio tracks in there too -- if I understood quick grouping right, it only adjusts faders of same type (meaning pressing ctrl+fader of a soft synth track would move all soft synth tracks simaltaneously, but not any audio tracks).

yeah, i found that grouping tracks works well, cuz when you move the fader, they all move together.
Is there a way to do a sub mix, like on Logic Pro X?

blu lacez
Is there a way to do a sub mix, like on Logic Pro X?

How does that work?