Aux Sends
An Auxiliary Send (or Auxiliary Send) is an audio output on a mixing console that creates a secondary mix independent of the main channels.
Think of an Auxiliary Send (Aux Send) as a signal "bypass". It allows you to take a copy of the audio from one or more channels and send it to a different destination, without affecting the main mix that goes to the audience or the recording.
Each channel on the console has one or more controls (usually knobs) to define how of that signal will be sent to the corresponding auxiliary.
All signals sent to the same auxiliary are summed and controlled by a general knob, the Aux Master, before leaving the mixer.Main Uses
Sending to Effects: This is the most common use. You create a mix for an external effects processor (such as a reverb). The "wet" sound of the effect then returns to the mixer via an Auxiliary Return. Stage Monitoring (Return): Creates a custom mix for the musicians' headphones or floor monitors, allowing each to hear what they need to play (also called a Cue or Artist Send). Pre-Fader vs. Post-Fader Auxiliary sends almost always have a switch to operate in two modes: Pre-Fader: The volume of the send is independent of the main channel fader. Even if you lower the fader, the sound continues to be sent to the auxiliary. Ideal for monitoring, as the musician's mix doesn't change when you adjust the main mix.
Post-Fader: The send volume is dependent on the main fader. If you lower the fader, the send volume also decreases. Ideal for effects, as the effect (reverb) follows the volume changes of the instrument in the mix.