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Overview of Audio Mixers

By March 14, 2014March 16th, 2016Audio


This blog is about mixers themselves. Be it analog or digital, they all share these 4 main components:

1.  Gain Staging – from Microphones, Direct Box’s, effects, tape from multi track recording, IPod’s and other sources.  This means from the stage, or in the studio.

2.  EQ – is for adjusting the hi’s, mid’s and low’s, for each individual channel or instrument.

3.  Mixing levels – faders, knobs, are for controlling “The Mix” of the over all levels of each source, to a stereo or mono out put.

4. Destinations / Routing – This is the end of the signal flow in a mixer.  Mains, aux outs, effects, monitors, Delay speakers, and other rooms.

Above are just some basic descriptions of these 4 functions of a mixer.  There are many more.  Some mixers have a “Power Amp” built in.  There are all kinds of different mixers to suite the needs for a job to mix sound for.

Pictures are a thousand words.  You can see by these different pictures, they come in all kinds of shapes and sizes to perform the needed job at hand.  Mixers can be on your computer, being totally digital like the Presonus Studio One, or Pro Tools Garage Band, Cube Base, Cake Walk, so on.

I will touch on the above (4) components very briefly:

(1). Gain Structure

This is “Highly” important due to this being the beginning of the signal path. If this is not set correctly, the results will not be good in many different ways. Gain structure varies from mixer to mixer.  Read your manual!  The Gain sets the incoming source for proper signal to noise operation and to avoid distortion.  This also sets up the 3 remaining functions in a mixer, (in the above list), on how they will react to one another. Set to low, you will have noise, Set high, you can have distortion. Remember to consider peaks in your music.  So make sure to look at Gain structure indicators such as, “Led’s” and Meters and adjust accordingly.

(2). EQ

EQ is used for adjusting the Hi’s, Mid’s, and Low’s of each channel thus the source coming into that channel, be it guitar, bass, drums, horns, violins, computer feeds, D.J. gear, and so on.  I think you get the idea. We are indeed talking about “Frequency’s here.  This can be difficult to understand, but it is necessary to learn.

This is where your ears really come into play. Listen carefully.  It’s also important to know, EQ will affect your “Gain”.  This sounds odd, but it does, so watch the level

on the channel being EQ’ed, you may have to refer back to your “Gain” on that channel. EQ’ing a channel is not intended to be used as a level control.  Be careful not to over EQ !!!!! This can cause noise, distortion and other un-wanted effects. If your having to EQ something by turning EQ knobs to almost the full travel of the knob, something is not right. Try changing the mic, or other settings that can affect the EQ. There is so much more this subject alone.

(3). Mixing Levels

This is the artistic part of using a mixer.  It is where all the ingredients have come together, from the above mentioned, to form the final out come of your work.

There is also a technical side to this as well as in watching the system limits for noise and distortion, so know your mixer noise floor and max out puts. The flavor you end up with for the audience is like baking a cake.  However watch your over all volume levels.  NOT TOO LOUD! You are in control of other peoples hearing.

(4). Destination / Routing

Destination is where your sound will end up and is the function of a mixer including the Main sound system, the monitors, effects, reverb, digital delays, and sound enhancing devices. There maybe other rooms that needs the sound to be sent to, Delay speakers in large rooms or out doors, maybe even headphones.

The “Routing” in the mixer, is how the signal gets to these destinations.  This can be done by switch’s, level control knobs, and faders. This is all done with in the mixer and can become confusing at times.  I encourage you to use your manual, read ALL the silk screen (printing) on the mixer to know where these outputs are, and what there connections are balanced, UN-Balanced, XLR, 1/4″ or RCA.


Mixers are like the center of an “Hour Glass”. It is where all the sources come into, then are Gain Staged, EQ’ed, then “mixed” by setting the level of each channel according to your idea of how the over all “Mix” will sound or the producer thinks it should sound. Then routed to the Destinations to be heard in those areas. It is very important to know your mixer, functions, and limits. Mixing is a blast. It is the Creative part of sound, but you must know the tech element as well for success.

This is my opinion as an engineer, it’s like dancing with the musicians, or dancing with the star’s as I have said before.  Done incorrectly, and you can make them sound bad, thus the term “Don’t mess with the sound guy”!  Done correctly, you can make them shine!

Have a great day…. until next time.

Wayne Carlson, Real Audio Workshops

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