An audio technique that employs separate channels of audio content that are directed to different speakers, often speakers configured to optimise a surround sound effect.

A sound recording/reproduction system with more than two channels and loudspeakers. Current systems have 5, 6 or 7 channels plus a low-frequency effects ( LFE) channel. Multichannel sound can also be simulated from two-channel sources. See Logic 7, Dolby ProLogic Plus.

Multiple channels of audio, usually containing different signals for different speakers in order to create a surround-sound effect.

means transmission of 4xstereo with various algorithms via IP, e.g. Eapt-X or transmission of 5.1 multichannel or 7.1 multichannel via IP or ISDN with various algorithms, e.g. AAC HE

In wireless microphones, generally refers to a transmitter or receiver which has more than one user-selectable operating frequency.