The Channel Strip

 

soundcraft spirit lx7 channel strip signal flowToday’s tutorial here on Pro Recording is about the Channel Strip as studied in Berklee College’s Introduction to Music Production online course. The channel strip is found on both analog mixing consoles as well as within digital audio workstations (DAW’s). I have based this lesson on an analog mixer because the basic principles are applied to the world of digital mixing as well. Check out the diagrams I included from a Behringer mixing board along with the Logic Pro channel strip flow and the Reaper channel strip flow which should give you a better grasp of what I am describing. Depending on the mixing board you have, these features may not be in exact order.

Input

Generally, the channel strip is the signal flow through the mixer from top to bottom. Starting at the top, the first thing you are going to find in any channel strip is an input. On an analog mixer, the input is going to be either a 1/4″ jack which will accept line level signals or an XLR jack which will accept microphone signals. On a digital mixer, the input will generally be the input channel on a digital audio interface, a media item or a midi item. The input may also come from another channel which is something we will discuss a bit later.

Trim Knob

behringer qx2442usb channel strip

Behringer QX2442USB channel strip

After the input, the next thing that you will find on an analog mixer is an input trim fader knob. This is a bit different than the digital world because on the computer, the input trim fader knob is usually located on the audio interface. The input trim fader knob will control the preamp’s level.

Inserts

Following the input trim fader knob, next you will find the inserts. The inserts are used for sending the signal flow to external effects and back. Inserts are connected using 1/4″ TRS cords that use the tip to send and the ring to receive voltage variations.

Aux Sends

reaper channel strip signal flow

reaper channel strip signal flow

The auxiliary sends are typically next in the channel strip of any pro recording mixing console. This is usually the only exception to the top-to-bottom signal flow as the aux sends are generally selectable between pre-fader and post-fader. Pre-fader means that the signal flow will be sent after the inserts. Post-fader means it will be sent at the end of the channel strip, after the volume fader. Aux sends are usually used for creating monitor mixes and may also be used for recording.

Equalizer

The equalizer comes next and it used for spectral manipulation where you can adjust the various frequency ranges indicated by the control knobs. On most high quality mixing boards, this will be a parametric eq. The equalizer may come before or after the auxiliary sends.

Pan Knob

The pan knob is usually located just above the volume fader. The pan knob controls the amount of signal going to the left and right channel of the track’s output. Rather than amplifying the signal, the pan knob only attenuates the signal to the opposite of where it is selected.

Solo/Mute Buttons

Below the pan knob, usually to the right of the volume fader, is the solo button. When the solo button is enabled, it silences the output of all of the other tracks. When multiple solo buttons are enabled, only those selected tracks will be heard. The mute button does the opposite.

Volume Fader

logicpro channel strip signal flow

Logic Pro channel strip signal flow

The volume fader controls the output signal of the track after it goes through the entire channel strip. A useful thing to watch out for is the Unity section (marked U) which will allow you to produce a healthy signal that is has not had gain applied in more than one instance.

Master

Digital Signal flow Worksheet Impmooc

Digital Signal flow Worksheet

The track signal then goes to the master section of the mix. Depending on the mixer, there may be more than 2 outputs. These are usually enabled using buttons to the right of the fader on the channels. The master section is usually a smaller, more simplified channel strip where all the selected tracks end up as inputs.

The Channel Strip – Pro Recording

I hope you have enjoyed this basic tutorial on the channel strip. I have based it on an analog mixer but the principles can be applied to the world of digital mixing as well. The digital world has more emphasis on inputs and outputs – where sound is coming from and where it is going to. There is many more routing options in digital audio workstations and more customization of the routing of the signal flow.

In summary, here is the channel strip as I discussed it:
Input
Trim Knob
Inserts
Aux Sends
EQ
Pan
Solo/Mute
Volume Fader
Master

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