The desk has two main sections: Inputs and Outputs. Although most sound desks look terrifying initially, they can be mentally broken down into simple sections. Once you understand the basic concepts, you'll see that all mixing desks are very similar. Inputs are where the sound signals come into the desk, and outputs are obviously where the sound leaves the desk. Any input signal (in the case above, there are 8 possible inputs) can be routed to any of the four outputs.

Spirit FX8 from www.spiritbysoundcraft.com

Input channels:

• Gain controls the sensitivity of the channel to the incoming sound. A low level microphone signal will require a high gain level. A higher input (from a CD player, for example) will need little or no gain.
• Equalisation (EQ) controls are used to adjust the tonal quality of the sound. Most mixing desks have two or three EQ controls for high, middle and low frequency sounds.
• Auxiliaries can be used for additional routing of sound to external devices.
• Routing switches control which of the outputs the sound is sent to.
• Pan control positions the sound in the stereo "image" of the output.
• Fader is used to control the volume of sound sent to the output. Most faders are calibrated in decibels, so that with the fader at the bottom, it's at infinity (ie no sound gets through). The optimum position for the fader is around 70% of the way up. This is normally marked 0db, and means the desk electronics are neither amplifying or attenuating (reducing) the signal - it's at it's optimum.

Output channels:

The inputs sent to each output are mixed together, and once the output channel is raised, the signal is sent to the output connector.