INPUT

COMPRESSOR

Virtual Audio Channel Strip

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Insert Compressor

Demonstrating audio signal flow including input trim, channel insert, channel EQ, and pre/post fader sends.

Use the play button above to begin. As you manipulate the controls in the virtual channel strip on the left, a description of each control will appear here.

Trim

The trim, or input gain control is used to boost or attenuate the signal arriving into the channel. As the first gain stage in the channel, this provides an opportunity to compensate for sources that are too soft or too loud, or to account for different types of input such as microphone signals (low level) and line-level signals (high level).

Insert

As the name suggests, insert effects are inserted directly into the signal path of the channel. 100% of the signal passes through the insert effect, rather than a portion of the signal (as with sends below). Commonly inserted effects include compressors (as we have here) and EQs. Due to the nature of their routing, insert effects have a 1:1 relationship with their channel.

High Shelf EQ

A type of parametric EQ, a high shelf EQ allows for an increase or decrease of harmonic content above a specified frequency, in this case 12kHz.

Mid Peak EQ

A type of parametric EQ, a mid peak EQ allows for an increase or decrease of harmonic content centered at a specified frequency, in this case 1200Hz. The "Q" value (fixed in this case at 1 octave) specifies how wide or narrow the boost/cut takes effect around the specified frequency.

Low Shelf EQ

A type of parametric EQ, a low shelf EQ allows for an increase or decrease of harmonic content below a specified frequency, in this case 100Hz.

Pre-Fader Send

A pre-fader send takes the channel's signal and routes a portion of it, specified by a knob or fader, to another location such as a separate monitor mix or effect. A pre-fader send performs this routing before the channel fader, so that the send acts independently of the fader.

A common application in a live sound reinforcement situation is to use the pre-fader send to create and control a separate monitor mix that is independent of the levels set by the channel output faders used for the front-of-house mix.

Used with a reverb effect as we have here, a pre-fader send allows for control of the wet/dry balance by controlling the send/fader respectively. Notice that with the channel fader pulled all the way down, the pre-fader send still sends its signal to the reverb, resulting in a 100% wet sound. This can be useful in the perceived positioning of sound sources forward and backward within virtual acoustic environments such as concert halls.

Channel Fader

The channel fader adjusts the final output of the channel's signal before it is sent on to its next destination, such as sub-group routing or final mix output.

Post-Fader Send

A post fader send takes the channel's signal and routes a portion of it, specified by a knob or fader, to another location such as an effect. A post-fader send performs this routing after the channel fader, so that the send acts in conjunction with the fader.

Used with a reverb effect as we have here, this allows for a consistent wet/dry balance as the channel output is adjusted. Notice that if the fader is pulled all the way down, the post-fader send is attenuated as well.

On most hardware mixers, the send knobs, whether pre-fader, post-fader, or switchable, appear above the output fader. I've placed the post-fader send knob below the fader here, to visually reinforce its routing position in the top-down signal flow.