Utilizing Busses

A bus lets you route a group of channels through a single point so you can process them together.

The water-pipe analogy

Think of a channel (say, the acoustic guitar) as water coming down a pipe. You can open a spigot that diverts some of that water elsewhere while the main flow continues. In audio, that’s sending a channel’s signal off to another destination. A channel’s output can go straight to the main stereo out — or you can route it to a bus first, and the bus then folds into the main out.

Why bus? Process a whole group at once

The classic use: put one effect on a whole group. To compress the entire drum kit (great in a broadcast mix), every drum channel is routed to a drum bus instead of straight to the stereo out. On a Yamaha console these buses are called mixes (e.g. mix 9–10 set up as a drum bus). The bus takes in all your already-mixed drum levels, you insert a compressor on the bus, and the compressed group folds back to the stereo output — gluing the kit into one cohesive instrument.

Set up a drum bus → send every drum channel to it → insert a compressor on the bus → fold it back to the main out.

Group compression on more than drums

Brian likes to keep the core components compressed separately as units: the drums as a unit, the whole band mildly compressed as a unit, and all the vocals (which already have individual compressors) under a very mild overall group compressor. It’s the icing on the cake — it keeps those core elements massaged and from getting out of control. (Advanced, and only if your console can do it.)

(Setup differs by console — read your manual or look it up for yours.)

Bus vs. DCA — the key difference

• A bus actually routes the audio to a group destination (so you can insert processing on it).
• A DCA passes no audio — it’s just a remote control for a group of faders. Pulling the vocal DCA down is exactly like pulling all the vocal faders down together, but the audio never flows through the DCA.

Use both: DCAs to ride levels of groups, buses to process groups.

Application

• Route all your drums to a drum bus and put a gentle compressor across it; A/B the glued vs. ungrouped kit.
• If your board allows, add mild group compression on the band and on the vocal group.
• Make sure you can explain bus vs. DCA — route audio vs. remote-control faders.