Warning! Super sound nerds only, everyone else should skip this section to avoid a brain owie.
So I covered a cool gating trick back on Day 181, now it time for a compressor technique that I find exothermally useful and is another of the secret foundations of mixing a rock show Dave Rat style. As live engineers we live in a spontaneous and real time environment, the less time we waste mucking about with stuff, the more time we have to actually focus on keeping the sound together. Described here is a method that not only will assist you in keeping the band's dynamic levels manageable, but it will also allow you to alter all your compressor thresholds without leaving the center console area. On an analog setup, this means you don't have to go to the outboard rack bend over and try and read the labeling on the knobs. On a digital console, this means that you can avoid sifting through a pile of compressor menus.
The trick is to assign each instrument type (for our purposes vocals are an instrument) to both a VCA and a subgroup. Then bus the subgroups to your L and R or matrix. For example; Take all your vocals and assign them to VCA 1 and also assign them to stereo subgroup 1 or mono subgroups 1 and 2. Then insert a pair of compressors on the vocal subgroups. This is where it gets cool. So now, since a VCA is really just a remote control for the channel faders, when you increase the vocal 'VCA' level it turns up the vocals pre-compressor causing more compression. When you raise the vocal 'group' faders it raises the post compressor vocal level, increasing volume after the compressor. If you raise the VCA while lowering the group faders then you are in effect lowering the threshold's of the compressors without changing the volume and without physically (or mentally in the case of digital boards) leaving the center of the console. Raising the group faders while lowering the VCA in effect raises the compressor thresholds resulting in reduced compression.
Follow me? Ok, so now repeat that same pattern on the guitars in stereo, bass in mono, kick and snare paired together mono, toms in stereo and cymbals in stereo and in this description you would end up with 10 subgroups (4 stereo and 2 mono) and 6 VCA's. You now have full control over pre and post compression levels on every instrument type. Further more, since you are compressing vocals as an overall stereo unit, if one person sings it may just barely compress but when all three singers sing at once, you will get more compression. This means that unlike using channel compression, with subgroup compression your overall vocal level will be more manageable. Same goes with guitars and so on. Pairing up the kick and snare and adding slight compression helps balance the two out a bit, fatten their sound and only ties up a single comp. I personally aim for equal level on kick and snare so the comp'ed pair helps dial that in.
If all that is not enough, check this out! Take your 7th VCA and assign all your inputs to it to make it an 'input master VCA' and then assign all 10 of your compressed subgroups to the 8th VCA making it an 'output master VCA'. This now is the most powerful of all as you can turn up input master VCA 7 and drive all your comps into compression while lowering output master VCA 8 to maintain a constant volume. These two master VCA faders give you the ability to change the over all dynamics of the entire mix similar to what a compressor on the Left and Right bus would do. Except this is better because each instrument group is independently compressed so the instruments are not all pushing each other down in volume.
And the reason this is so cool is that it will bring you one step closer to reaching that goal of being in total control over everything necessary without having to look away from watching what is going on and only moving your hands and remaining relaxed, happy and enjoying the thrill of the show. Hey, wait a minute, that is kind of like driving a race car.