Original Source:http://www.mediacollege.com/audio/mixer/channel.html

Each input source comes into the mixer through a channel. The more channels a mixer has, the more sources it can accept. The following examples show some common ways to describe a mixer's compliment of channels:

Original Source:http://www.mediacollege.com/audio/mixer/intro.html

A sound mixer is a device which takes two or more audio signals, mixes them together and provides one or more output signals. The diagram on the right shows a simple mixer with six inputs and two outputs.

As well as combining signals, mixers allow you to adjust levels, enhance sound with equalization and effects, create monitor feeds, record various mixes, etc.

Mixers come in a wide variety of sizes and designs, from small portable units to massive studio consoles. The term mixer can refer to any type of sound mixer; the terms sound desk and sound console refer to mixers which sit on a desk surface as in a studio setting.

Sound mixers can look very intimidating to the newbie because they have so many buttons and other controls. However, once you understand how they work you realise that many of these controls are duplicated and it's not as difficult as it first seems.