What Does a Mixing Desk Do?

A mixing desk is also sometimes called a mixing or recording console, or just a console. Regardless of what we called it the function of the mixing desk is to take sounds from different microphones and other sources and mix them together, as the name suggests.

The desk acts as a central hub for much if not all of the equipment in a studio. It has inputs into it, such as:

• Microphones
• Line inputs - such as keyboards, effects units etc.
• Other inputs - such as tape inputs, multitrack recording device inputs etc.

Each input can be assigned to an individual track on the desk. For example, we could have:

• Input/Track 1 - vocals
• Input/Track 2 - guitar
• Inputs/Tracks 3 and 4 - keyboard
• Input/Track - bass

The desk carries out the process of mixing all of the inputs together, as well as possibly:

• Altering the sound via effects
• Adding equalisation 
• Panning (balancing) each individual track for stereo effects
• Altering the volume of each track relative to the others

The output from a desk is usually a mixture of all of the tracks and is "sent" to an external recording device, such as a tape recorder.

The Desk Layout

Mixing desks often look very complex. However, every desk is laid out in pretty much the same way. We always start at the top of a desk (the input section) and work down through the process section towards the faders (the output section). 

Mixing desks have anything from four to over 100 tracks. Each track on the desk will have the following controls:

In addition to the controls for each track there are usually other controls that affect the whole desk such as:

• Overall volume - the overall volume that is output from all of the mixed tracks
• Control room volume - i.e. to control the volume that is heard in the control room
• Auxiliary setting controls - for altering the properties of any attached equipment such as reverb units
• Output controls - such as buttons that when pressed send the output to different devices such as speakers or tape units etc.

These controls are usually grouped together either at the right-hand side of the desk, or at the centre of the mixing desk if it is very large.

The following picture shows a simple, mini-desk. Try to identify each section of the desk:

Groups

Consider the following situation. A drum kit has eight microphones covering each individual element of the kit. The engineer decides that the whole kit sounds just a little too loud and so adjusts the individual volume controls for each of the eight tracks on the mixing desk. She then decides that she has overdone it and so needs to re-adjust each of the eight tracks again. This is time consuming and laborious.

In order to overcome this problem larger desks have group controls. Each individual track can be assigned to a group. For our example above we could assign all eight drum tracks to group controls 1 and 2. Now all we have to do is adjust the group controls and all eight individual tracks will be adjusted.

Group controls are usually near the output section of a mixing desk and the faders (i.e. volume controls) for the groups are usually on the right-hand side of the desk.

Mixing desks are defined by how many tracks and groups they have, as well as the sort of output delivered, such as stereo. A desk with 24 tracks, 8 groups and with stereo output is a 24:8:2 desk. 

Mixing desks vary greatly in size but come in two main types:

• Analogue

• Digital

Analogue
An analogue desk is one that does not use internal computers for any sort of parameter control.

Each individual function of the desk has a separate controller. For example, if there are four auxiliary inputs there will be four auxiliary controls on the desk. Professional analogue desks are often very large so as to accommodate all of the individual controllers.

Analogue desks are now starting to disappear in most studios.

Digital
A digital desk is basically a computer system in the form of a mixing desk.

Because the desk is a computer it is possible to have "virtual" controls. For example, the desk may only have 16 faders (track volume controls), but 32 track inputs. At the flick of a switch (or click of a mouse) the track faders switch from tracks 1 to 16 into the faders for tracks 17 to 32. Likewise, the desk may only have a single controller for an auxiliary, but the desk may have up to 12 auxiliary inputs. Again, by pressing a button it is possible to cycle through each of the available auxiliaries from 1 to 12.

The virtual nature of digital desks means that a lot more can be packed into a much smaller unit. For that reason digital desks are usually much smaller than their analogue counterparts.

In addition to the virtual nature of digital desks they also contain a great deal of automation. For example, on an analogue desk we have to move each of the faders by hand. On a digital desk the onboard computer remembers any movement we make to the faders (or anything else for that matter) and can play those movements back. This makes it a very powerful tool for mixing different tracks together as well as copying controller settings from one track to another etc. 

Digital desks are still comparatively expensive but prices are coming down rapidly.

Hybrid
Some desks are hybrids between analogue and digital. For example, some analogue desks have automated faders or other controls, while not having any virtual tracks or controls. This keeps the cost of the desk to a minimum while at the same time allowing for some of the processing power of a digital desk.

Mixing Desk Pictures