Sunday, July 28, 2013

HEADROOM AND GAIN STAGING! a guide for dummies PART 2/2


In the first part we have seen how to optimize the signal-to-noise ratio (click here for an in depth article) while preserving headroom when recording audio.
What do we mean with signal-to-noise ratio? It's the ratio that measures how effectively we have recorded our signal: below a certain level we have nothing but noise, so if we record a sound with a too low input gain it will be recorded very low, and if we will raise the volume fader of our DAW at a level sufficient to make it audible, we will have also the background noise raised significantly.
The ideal therefore, would be to have the sound tracked at an input gain high enough to make it be acquired from the DAW at the optimal distance from the background noise, so that we won't need to raise the track volume excessively, therefore the noise won't be heard.
On the other hand the signal must be far enough from clipping, otherwise we'll have to deal with unwanted distortions, that are even harder to treat than background noise.

During the Mixing Phase, as we have already seen, we'll have to deal with the single tracks making sure that everything is euphonic and perfectly audible, and to do so we can process the single tracks, process them in Groups and/or process the whole mix buss as it is already one single track.
The Mix Buss (also called Stereo Buss) is the DAW channel in which all the single tracks pass, and its volume fader affects all tracks at the same time, so we must be very careful when loading plugins on the insert of this track, because its effects will be cascading on every track, especially when talking about compression.
Mix buss compression in facts will affect each track and will sum with the single tracks compression, so we must keep it very low with settings, just to attenuate the occasional peaks, and lower accordingly the settings of the compressors on the single tracks to not drain excessively the life of the sounds: we must not forget in facts that we're going to compress and limit the sound rather heavily in the Mastering phase too.
Everybody has a different vision about Mix Buss compression; in my opinion, I prefer to compress to perfection the single tracks so that, unless I'm not working on a live recorded track with strange dynamic problems, there won't be need to attenuate and normalize peaks on the mix buss, leaving the general sound a bit more dynamic.
The overall sound that passes throug the mix buss should never be higher than -10 dbFS, that way there will be enough headroom to work on the exported tracks in the Mastering phase; if the track volume is already too high, very little mastering improvements can be applied, so we must lower the master volume until our peaks are in that area.

Once we have everything on its place, whether the peaks are compressed on the single tracks and on the mix buss, and the volume is automated (this is another solution to avoid excessive compression that can harm the tone), it's time to Master the song.

In the Mastering Phase we can greatly improve the song or completely ruin it, especially with gain staging matters.
Let's start with the condition that we have perfectly respected all the rules exposed on this article: we have recorded everything at the proper levels (eg. -10dbFS), we have mixed with a transparent compression and exported the tracks at -10dbFS, pristine clean, balanced, with good dynamics (= not already squashed) and without distortions:  the ideal it's to load on the last slot of our DAW a metering tool such as the TT metering tool (which will also give us a judgement about the gain structure of our song, if it's gonna be ear fatiguing or pleasant) and proceed with some final compression.

In this phase we have 2 solutions: to use Multiband compression, which will help us in correcting also some mix problems, such as adding some low end if the general sound it's too weak, or to compress just the mix areas that needs to be processed bypassing the others, OR to use broadband compression (single band compression): this solution it's probably the best one if we're happy with our mix and don't want to change the overall balance (actually, 7 times over 10, to alter the mix in the mastering phase will result in a disaster, if we don't know EXACTLY what we're doing).
To compress in the mastering phase can make us lose some Transient, in this case we can use a Transient Shaper to bring back some of the wave parts we are squashing (but the ideal would be to squash as little as we can, so that we can avoid this remedy), and if we have used mix buss compression but we feel the mastering compressor is harming our sound, my suggestion is to go back in the mixing project and to remove the mix buss compressor: the mastering one will probably sound more transparent and pleasant, and in my opinion it's more important than the mix buss one.
Usually a mix buss compressor in facts is used as an alternative to the mastering compressor we can use to mix hearing an already compressed sound, so that we can compress less the single tracks, and it's rarely a good idea to sum up single track compression, mix buss compression, mastering compression and limiting altogether, as the TT Metering tool will probably tell us.
My suggestion is therefore to choose between Mix Buss compression and mastering compression, not to use both of them, but this is not a general rule: many producers thinks that it's a better idea to use both.

Once we have prepared the mix by lowering the peaks with the mastering compression, it's time for the ultimate gain processor: the Limiter. This is the wall in which all of our tracks will be pushed, and the more we will push them by lowering the threshold and raising the ceiling, the more the volume will raise, the more transient we will lose, and eventually the sound will start distorting.
Since today most of our music will probably be heard on Youtube or on some low quality mp3, it's a good rule to set the ceiling at -1.0db, it will prevent unwanted distortions, and the threshold should be lowered until we see a little of gain attenuation, -3/4db at maximum, because if we push more we will probably waste all the careful work we have examined in these two weeks, to preserve the gain structure of our mix and to result in a dynamic, clear, pleasant song.


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  1. Again, and again, great tutorials! BTW I'm totally in favor of keeping the dynamics of tracks to keep the music more organic and natural, and not ear fatiguing... I've been getting that a lot with these modern rock albums. THANKS for your info and time!

  2. thank you man for following me! if you want you can also collaborate with us, anyway share the blog! :D