Busses

A few weeks ago, I talked about auxiliary tracks, what exactly they are, and what makes them different than other tracks in a producer's DAW. I did this so that I could more clearly explain what an effects send is and how it works.

This time, I'll explain what a bus is and how it works.

For the record, auxiliary tracks can be used for more than just effects sends. An auxiliary track can be used to group several other tracks, like drums or vocals.

Again, auxiliary tracks don’t produce any audio of their own. They only relay.

But to what do they relay the information they receive from elsewhere?

Well, they relay whatever audio they receive (and sometimes modify) to the output that the producer has chosen. For me, in most cases, this is the master fader.

But technically, a producer can route an auxiliary track to a number of other outputs, including a physical output, a bus, or another auxiliary track. What’s important to the listener is not the route the audio takes to get there, but instead how it sounds once it gets there.

So what determines how it sounds?

Well, a few things, including both the auxiliary track’s plugins and its fader. The plugins determine which effects will be blended with the original track’s audio, and the fader determines how much it will be blended into its output, or for me, the mix as a whole. I usually keep my auxiliary tracks turned up to 0 dB and control the amount of blending with the actual “send.” More on that later.

Let’s talk about how the blending happens.

Let’s say a producer wants to add a delay to a vocal track, but he doesn’t want the effect to “mask” the vocal. He wants to blend it subtly with the dry vocal.

So he creates an auxiliary track, and then he adds a delay to that auxiliary track. Now how does he get the vocal to pass through the delay if the audio clip is on the original vocal track?

Well, he will need to send the vocal track to the auxiliary track, which will leave the vocal track itself in tact and duplicate its audio on the auxiliary track, where the delay will take effect.

But how does a producer do that, send audio from one track to another?

Let’s backtrack for a moment. Every track has both an input and an output, a source and a destination. A vocal track, for instance, might have a physical input, like the XLR jack on a recording interface.

But most of the time, an auxiliary track will not receive audio from a physical input, but rather from a digital input, something we call a “bus.”

A bus is almost exactly what it sounds like. It’s the vehicle, or more accurately the pathway, by which a producer’s audio “travels” from one track to another. If the auxiliary track is the destination, then the send is the map, and the bus is the route the audio takes to get there.

So somewhere on the original vocal track’s fader, there will be the option to send. A producer can send a track to virtually as many busses as he wants, but in this case, he will want to send the vocal track to the same bus used as the input for the delay’s auxiliary track.

A send is a lot like a fader, in that it has a controllable level. It can even be automated.

So the producer will want to decide how much of the original vocal track he wants to send to the auxiliary track, and this will depend on what level of audio he wants affected by the delay.

As I mentioned earlier, I usually like to start with the auxiliary track fader at 0 dB and blend the effect to the desired amount with the send level. In some cases, this level will remain constant for the entirety of the track, and in other cases, I’ll automate the send in order to achieve a different amount of the effect at different times in the song.

From there, if the auxiliary track’s fader needs to be adjusted, I can do so, but most of the time, I like to leave that door open for the entirety of the song and try to control the more minute details of the mix as deeply within the tracks and plugins as possible.

This kind of minimalism helps me keep my session organized. To approach a mixing goal from too many directions can create complex challenges that will slow down a producer’s productivity. I prefer to have a consistent workflow that keeps me moving and allows for creativity between the checkpoints.