What Does an Audio Mixer Do?

Audio Mixer and Sound Board

It has as many names as it does purposes. Whether it is known as a mixing board, mixing desk, mixing console, or sound board, an audio mixer is a key component to managing either recorded or live event sound. It is extremely likely you have been to dozens of events where an audio mixer was used and yet, very few people understand how audio mixers work and what exactly they do. This article will lift the veil on the inner workings of the audio mixer.

What does it do?

At its core function, an audio mixer takes two or more audio signals, merges them together and provides one or more output signals. Think of the audio engineer at the controls like an orchestra conductor, ensuring all of the individual sound sources mesh together in one harmonious end product. To do this, he or she will use the audio mixer to filter and optimize sound by adjusting levels, enhancing sound with equalization and effects, creating monitor feeds, and recording various mixes.

What are the Key Components?

  • The Board – This is the overall layout for the various controls. There are two basic layouts for the board, in-line and split. In-line consoles have both the input section and the monitoring section contained within the same channel strip. Split mixing consoles have them located in different halves of the board.
  • Inputs – The inputs are the entry point for the various sound sources into the audio mixer. They connect to the mixer through plug-ins usually located at the rear of the unit. The most common audio inputs are:
  • XLR
  • 5 mm jack
  • RCA
  • Channel Equalization – Simply put, this allows you to adjust and control both the treble (high frequencies) and bass (low frequencies) for each channel.
  • Auxiliary Channels – Commonly known as “aux” channels, these allow you to send sound a secondary feed of the channel to another device, most often for monitoring purposes (i.e. The bass player only wants certain elements in his monitor, or a recording needs ambient mics that the live environment does not).
  • Assign & Pan – This function allows you to direct certain channels to one of the two stereo outputs. If you were mixing sound from a large band, you could have all the brass instruments on the left output and the strings on the right.
  • Faders – These are the sliders that allow you to either raise or lower the presence of each individual channel as it goes into the final output or mix. These are perhaps the most important tool at your disposal when using an audio mixer. It is recommended to start with all channels set at 0dB and then adjust accordingly.

Where Would You Find Audio Mixers?

The most obvious place is in any kind of sound recording or post-production studio. You cannot record an album or work on a film soundtrack without them. But they are not only found in large technical sound recording operations. You’ll also find them in DJ booths at clubs or any event with a PA system. So the next time you attend your cousin’s wedding and you hear the best man’s mic fade out in the middle of his terrible toast and music fades up in its place, you’ll know it was done by someone behind an audio mixer.