Using Aux Busses
Aux busses can have many functions, and offer many advantages in the mixing process.
They started out on analog mixing boards. A basic mixing board is laid out with several channels, which get summed together into a stereo left and right output. Then one day, someone decided it would be nice to have another output on the mixer, and give each track independent control of being sent to this output. Since this is an auxiliary output, and it can contain a mix of several channels, it got called an aux bus.
This was useful because let’s say they had a hardware reverb unit, they could send just the right amount from each track to the reverb unit, and then send the signal from the reverb unit back into the mixer. This provides the ability to easily add or remove reverb from any track.
Some mixers have 4, 6, or even 8 aux sends. Let’s say you have a 4 piece rock band, you could all plug into the mixer, and plug headphones into the aux outs. That way each artist will have a custom headphone mix by adjusting the aux volume on each track.
Essentially, what the aux send does is create a duplicate of the track, and sends it somewhere. In the context of using aux busses in the DAW, the aux signal will get processed, and sent to the output along with everything else.
Most DAWS will allow custom settings, but the way I use aux busses is to place them after the effects, and post fader. This way, all the effects I add to the track remain on the aux send. However, the effects of one aux send does not effect what gets sent to the other aux sends.
So here we have a track, with the output set to stereo output. Now let’s insert a send, I can chiiise any number, but I’ll just choose aux 1. As you see, aux 1 has its output set to the stereo output. Since there are no effects o. The aux bus, as I send signal to it, it will simply raise the output volume. That’s because I’m duplicating the signal, sending it to the aux bus, and then blending the 2 signals together in the stereo output.
What I like about using aux busses, is that I insert effects without effecting the rest of the track. So I’ll insert a reverb, set it 100% wet, because if any of the original track comes through it will only result in a volume increase. I don’t want a volume increase, I only want the effect. So now, I can adjust the amount of reverb by dialing in the amount of the send. And I can add another reverb on aux 2... just because I want to. So the original track signal, unaffected by aux 1, is sent to aux 2 so I can blend in that reverb to taste. If I didn’t have aux sends, I would have to apply the first reverb to the track, and then the second one after it, which would be adding reverb to the reverb. And if I wanted to add delay.. should I put it before the reverb and have reverb added to the delay? No, I don’t want reverb on the delay, so I’ll put the delay on aux 3... bam, now it’s unaffected by the reverbs on aux 1 and aux 2.