What is a bus audio input?

An audio bus is a pathway along which an electrical signal flows to transport sound from one part of the mixer to another. A bus audio input is a sound source for an audio bus that can be grouped with other inputs into a single bus.

A bus is part of a mixing console and ends with an aux out or a main bus out, which is the main audio output of the console. A bus can consist of groups of audio inputs and is often used to group together types of instruments, such as a drum kit or set of guitars.