What is Mixer?
A mixer is an audio device with one or more lines. It need not be designed for mixing audio signals. A mixer that actually mixes audio has multiple input (source) lines and at least one output (target) line. The former are often instances of classes that implement SourceDataLine, and the latter, TargetDataLine. A mixer can accept prerecorded, loopable sound as input, by having some of its source lines be instances of objects that implement the Clip interface.
A mixer is really a traffic manager. A signal is connected to an input, and you steer it to one of several possible outputs. Some mixers have several stages of mixing, where inputs are mixed to submixes, or groups, and then the groups are further mixed to a stereo output. For instance, you might have five mics on a drum set, and group these so one fader controls all drums. Trombone, tuba and trumpet might go to a group for horns, etc. Groups usually have the same assignment flexibility as individual inputs.
The functions of a mixer are:
1) Process input signals with amplification and EQ
2) Combine those signals in a variety of ways.
Each incoming signal goes into its own channel with its own processing controls. Mixers are often quantified by their number of channels – an eight channel mixer can take eight separate audio inputs, a sixteen channel mixer, sixteen inputs, and so on.
Mixers controls have the ability to balance out volume levels among different audio sources. For example, in a system with two mics for two presenters, if presenter A is soft spoken, the mixer can adjust A’s microphone level to match the level of presenter B. More advanced mixers have more advanced controls.
The mixer then routes the signals to an output channel. “Mixing” is the process of combining different audio sources or tracks and blending them for the best sound quality and balance. A good mix will result in the most realistic sound for the listening audience.
Audio from the input channels can be blended and output into one channel for monophonic sound, two channels for stereo sound, or multiple channels for surround sound. Mixers can be identified by how many inputs and outputs they have. For example, a mixer with 8 input channels and 2 output channels would be referred to as an “8 in and 2 out” mixer. In other cases multiple channels can be mixed to multiple channels for professional recording or home theater mixing. In a recording studio, a mixer might blend sixty-four separate channels into twenty-four to make a twenty-four track recording.
Many mixers are automated by computer and store presets, control settings, and various mixing moves. Automated mixers should not be confused with automatic mixers. Automatic mixers automatically turn mics on and off when volume levels are above or below a certain threshold.
Mixers may also be called consoles, boards, mixing consoles, mixing desks, all of which do essentially the same thing: they combine and reroute signals with a little processing and adjustment.