Mixing Console

The mixer is the device used to adjust relative volumes, pan positions and frequency content of tracks.

Mixing console
Figure 1 - Hardware mixing console

The primary job of the mixer is to combine two or more audio signals onto a single channel output.

Additional controls allow independent adjustment of levels through fader adjustments, stereo placement via pan controls, equalization adjustment via bass and treble pots, and finally, effect and processor mixing via an insert or send/return facility.

Some form of metering is usually provided to inform the user of the signal levels entering the mixing console. Temporary silencing and soloing of a sound are possible using mute and solo buttons.

Although the concept of mixing sounds is simple enough, it can take many years to master the process successfully.

Common Mixer Controls

Mixers have several identical channel strips with each having a range of features with a variety of controls. These include:

  1. Channel Inputs: Each channel features either a mono or stereo input for connecting audio devices. Most mixers usually have an XLR input for microphones. For condenser microphones, there is often a phantom power switch.
  2. Gain Control: The gain controls the level of the signal entering the channel.
  3. Equalization Controls: The equalization controls are used to cut or boost the bass, mids, and treble frequencies.
  4. Aux Sends: The 'aux sends' control the level of the auxiliary output to other devices such as an effects unit or creating a headphone mix.
  5. Effect Send: The 'effect send' controls the level of any connected effect devices.
  6. Pan Control: The pan control sets the left/right position of the channel in the stereo field.
  7. Mute/Solo: The channel mute button silences the output of that particular channel when pressed. Activating the solo button silences all other channels but the one selected.
  8. PLF: PFL means Pre-Fade Listen. Its function is to listen to the channel's audio at a point before the fader takes effect. The PFL button is usually located just above the channel fader. 
  9. Channel Fader: The channel fader is a sliding control, or sometimes a pot (potentiometer), used to control the output level of each corresponding channel. 
  10. Channel Meter: The channel meter is a visual representation of the channel output level. If the signal level pushes the meter into the range of the red area, try lowering either the output level of the device connected to the channel, or the channel fader itself, to avoid distortion.
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