In professional audio, a mixing console, mixing desk (Brit.), or audio mixer is an electronic device for combining—also called "mixing"—(Brain, n.d.), routing, and changing the level, tone, and/or dynamics of audio signals. A mixer can mix analog or digital signals, depending on the type of mixer.
Mixing consoles are used in many applications, including recording studios, public address systems, sound reinforcement systems, broadcasting, television, and film post-production. An example of a simple application would be to enable the signals that originated from two separate microphones (each being used by vocalists singing a duet, perhaps) to be heard through one set of speakers simultaneously). When used for live performances, the signal produced by the mixer will usually be sent directly to an amplifier, unless that particular mixer is “powered” (Brain, n.d.).
Each signal that is inputted into the mixer has its own “channel.” Depending on the specific mixer, each channel is stereo or monaural. On all mixers, each channel has an XLR input, and many have RCA or quarter-inch line inputs. Each channel on a mixer always has a linear pot, or potentiometer, controlled by a sliding volume control, that allows adjustment of the level, or amplitude, of that channel in the final “mix” (Brain, n.d.). A typical mixing console has many rows of these sliding volume controls. Each control adjusts only its respective channel; therefore, it only affects the level of the signal from one microphone or other audio device.
Above each control, there may be several rotary controls (knobs) that attenuate the signal to that channel and that equalize the signal by separately attenuating a range of frequencies (e.g., bass, midrange, and treble frequencies). On the right hand of the console, there are typically one or two master controls that enable adjustment of the console's output level. Prior to the master controls, there may be an intermediate set of outputs and inputs for the addition of an external equalizer or audio effect, such as delay or reverb. Finally, there are usually one or more VU meters to indicate the levels for each channel, or for the master outputs, and to indicate whether the console levels are overmodulating or clipping the signal. All mixers have at least one additional output, beside the one main output. The operator can vary the mix (or levels of each channel) for each output. All mixers also have equalizerss of varying sophistication (Brain, n.d.).
Most, but not all, audio mixers can
- add effects.
- use monaural signals to produce stereo sound by adjusting the position of each signal on the soundstage.
- provide phantom power (forty-eight volts) required by some microphones.
Examples of mixing consoles and their manufacturers
References
