Friday, November 27, 2015

Using Aux Tracks

Many more possibilities open up when you explore the world of buses, aux tracks and sends — and
we'll do that right now, starting with a classic mix technique.

Here's a little scenario. You've got 20 audio tracks, and they all need reverb in differing amounts. Surely it's just a question of instantiating a reverb plug‑in on each? Well, it's not out of the question, but it'd be a terribly cumbersome way of working. First of all, the CPU hit of 20 reverbs could be colossal — potentially crippling if your computer is already maxed out. Second, configuring all those reverbs is very labour intensive, with way too much room for confusion. What's needed is a way to share one reverb flexibly amongst those 20 tracks — and it's easy. We're going to set it up on an aux track, a track type that you can't record on (although it can still be automated) and whose purpose in life is as a routing tool. Next, we'll configure the specialised extra outputs on the audio tracks — their aux sends — to split off some signal from each, destined for the reverb. Then you can tie the whole lot together with a bus. 

A technique that comes up frequently in SOS's interviews with great producers and engineers is parallel compression. Often used to supercharge drum overheads, in essence it's all about splitting the track's signal in two, applying aggressive compression to one 'half', leaving the other alone, and blending to taste. Parallel compression can create seriously dynamic‑sounding drum tracks. Most compressors won't have a wet/dry mix control, but if yours does, set it to 100 percent wet. Signal now begins to flow through the aux track, and its compressor, in parallel with the dry track — hence the name of the technique. One extra thing to think about here is whether the aux send is operating post‑fader or pre‑fader. What's the difference? Well, if it's post‑fader (which it'll be by default), as you adjust the drum track's main level fader, the send level changes too. If it's pre‑fader (which it will become if you click the send's little button), the send level is completely independent from the track's level fader. For parallel compression, I like to work pre‑fader, as then I can adjust the relative levels of the dry and compressed drums on their main faders with no fear of unpredictable level interactions as the mix takes shape. 

Recently, the Sonar family released the Jamaican Plain update which allowed the use of Aux tracks and Patch Points within the main track window. This has been a major upgrade to my effeiciency. Below is a video where I use some of those features similar to the areas SOS covered up top.