What Is An Aux Track?

Analog  mixing consoles just like Digital Audio Workstations possess a number of tracks.

For example, you can connect a microphone to a channel and record directly into that track.

If you’ve been in music production or simply work in audio production, then you’ve obviously encountered the term “aux track”…

It’s an important part of mixing and audio production and I’m going to use this article to take you in to what aux tracks actually are.

Without wasting too much time…let’s get into it.

So, what is an aux track?

An auxiliary track or aux track is a track that accepts signals being sent to it from various different tracks; an aux track is not like a regular track because you can’t record audio to it.

The signal that gets sent to an aux track is simply a duplicate of the original.

Therefore, it allows you to apply processing to the duplicate signal without affecting the original track’s signal. Thereby protecting its integrity.

An aux track offers you control and leverage over the mix between the dry original track and wet aux track signals.

A digital aux track in your DAW pretty much functions similar to an aux input on a hardware mixer …

as a destination for routing signals, whether audio that was recorded on another track or tracks or that is being input from an external source.

Audio entering into the aux track doesn’t get recorded in that aux track,

it only passes through and allows the engineer to use plugins or external

hardware to apply processing to the audio signals.

Audio can hence be processed using plug-ins and sent to another destination, such as the 2-bus output, another aux input, an audio track, or to a hardware output from the DAW’s audio interface.

Aux sends

An aux-send or auxiliary send is simply an electronic output for signal routing that is used on multi-channel sound mixing consoles….mostly  used in recording and broadcasting settings.

The signal from the auxiliary send is often routed through audio processing effects units such as reverb, digital delay, compression, etc and

then returned to the mixer using an auxiliary return input, therefore creating an effects loop.

This allows effects to be added to an audio source or channel within the mixing console or the mixer in your DAW.

Another common use of the aux send mix is to create monitor mixes… for  stage performers’ monitor speakers or in-ear monitors.

The aux send’s monitor mix is usually different from the mix that is being heard by the audience.

The two types of Aux Sends

The routing configuration and overall usage of an aux-send will differ according to the application.

There are generally two types of aux-sends, namely the pre-fader and post-fader.

Pre-fader sends are not affected by the main fader for the channel. However post faders operate oppositely….

The post-fader sends are affected by the position of the main fader slider control for the channel.

In a basic sense, a post-fader aux-send output is connected to the audio input of an outboard…

that is, an external unit that is not part of the mixer console…audio effects unit.

The audio output of the outboard unit is then connected to the aux-return input on your mixer or,

alternatively, it can be looped back to one of the console’s unused input channels.

A post-fader output is used in order to prevent channels whose faders are at zero gain from affecting the effects-return loop with hiss or hum.

Mixing consoles most commonly have a group of aux-send knobs in each channel strip, or, on small mixers…

you’ll find a single aux-send knob per channel…where one knob corresponds to each aux-send on the board.

The controls enable the engineer to adjust the amount of signal that will be sent from its corresponding channel into the signal bus routed to its correlating aux-send output.

The single most important benefit of using an aux-send is that it allows the signals from multiple channels on a mixer to be simultaneously routed to a single outboard device.

For instance, audio signals from all the channels of a sixteen-channel mixer

can be routed to a single outboard reverb unit so that all channels have reverb….or routed to a single reverb channel on your digital workstation.

The aux-sends from a group of inputs can also be easily routed to an

amplifier and then sent to studio monitor speakers in order for the musicians to hear their singing on stage.

The benefit of using the pre-fader aux-send function is that the volume of

the vocals or instruments in the monitor mix does not have to be the same as the mix heard by the audience.

This means that musicians whose voices are can be barely heard in the audience mix, such as backup vocalists,

can easily have their sound clearly sent through a monitor speaker so that they can hear themselves sing and ensure that their pitch and timing is on point.