The mixer combines and adjusts volume, pan positions, frequency content and more, of audio tracks.

Fig 1 - Mixing console

Traditionally, mixing was carried out on a 48 channel analogue mixing console within a professional studio environment. Nowadays, most people are mixing within their own personal studios using digital audio workstations (DAWS) on a personal computer or mobile device.

DAWS offer built in mixers, synthesizers, plug-ins and many other hardware counterparts at a fraction of the cost of hardware.

Whether mixing on a 48 track analogue mixer or within a self-contained DAW, the mixing technique is pretty much the same for both.

The 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, tone (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 is possible using mute and solo buttons.

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

Common Mixer Controls

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

  1. Channel Inputs: Each channel features either a mono or stereo input for connecting audio devices. With a stereo track, the left input should be used when manually connecting a mono signal source. Most mixers usually have an XLR input for microphones. For condenser microphones use the phantom power switch.
  2. Gain Control: The channel gain controls the level of a signal entering the desk.
  3. EQ Controls: The equalization controls are used to attenuate (cut) or boost the treble and bass frequencies.
  4. Aux Sends: The aux sends control the level of the auxiliary output to other devices such as an effects unit or creating headphone mixes.
  5. Effect Send: The effect knob 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 and Solo Buttons: 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. It's 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. Note: When you press the PFL button, the main monitor output will stop monitoring anything else and the only audio will be the selected PFL channel(s). Note that all selected PFL channels will be monitored, so you can press as many PFL buttons as you like. The PFL usually takes over the mixer's metering display. PFL is useful when setting the initial input level of a channel, as it reflects the pre-fade level.
  9. Channel Fader and Meter: The channel fader is a sliding control, or sometimes a pot (potentiometer), used to control the output level of each corresponding channel. The name comes from "fading in" and "fading out" tracks. The 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.