In all three of the scenarios we've gone over, the band has needed a mixer. To help you recognize the typical features found in a mixer, let's take a look at one of the simplest mixers available today: The Peavey RQ 200. This is a six-channel analog mixer and is about as simple as a real mixer can get.
No matter how simple the mixer is, it will have the following features:
- The ability to handle two or more inputs and mix them together - The multi-channel aspect is the essence of a mixer -- if it can handle only a single channel, it would be called an equalizer or a pre-amp, instead. Typically, the mixer will have an XLR input for each channel, and may also have RCA or quarter-inch line inputs as well. Each channel can be mono or stereo depending on the mixer. On the mixer's panel, there will be a linear pot (also called a slider or a fader) that lets you set the level for each channel you're mixing. The Peavey RQ 200 has six channels.
- The ability to send the mixed signal, known as the main output, to an amp - Powered mixers have an amp built in. Unpowered mixers are more common and require a separate amp, with the mixer providing the main out for the external amp.
- The ability to create a separate monitor output signal with its own levels for each channel - Normally, a knob is available on each channel to set the monitor level for that channel. A monitor out on the mixer can then connect to a monitor amp.
- Some sort of EQ of varying sophistication depending on the mixer - The Peavey 200 has a high and a low gain control to cut out or accentuate high (above 10 KHz) and low (below 70 KHz) frequencies.
Most mixers can:
- Add effects, such as reverb
- Produce stereo output from mono inputs - You adjust the "position" of each channel in the left/right mix.
- Provide phantom voltage (48 volts) needed by some microphones
More sophisticated mixers can provide all sorts of additional features. For example, you can find mixers with two or more auxiliary outputs, with a different mix on each output. And, digital mixers can accept and produce digital signals. The sky is the limit, really -- unless, of course, you're on a budget.