Multichannel usually refers to audio streams with more than two channels. The most usual multichannel setups are 5.1 (five main channels: front center, front right, front left, rear right, rear left and one Low Frequency Extension channel) and 6.1 (the five channels from 5.1 + back center).

Formerly limited to movie theaters, multichannel audio has became popular since the introduction of the DVD video format. The two competitors to the title of CD successor, DVD-Audio and SACD, can also offer multichannel content.

Some formats that support multichannel encoding are: AAC, Ogg Vorbis, WMA Pro, AC3, DTS, FLAC and WavPack.

There's no standard channel mapping for multichannel streams, and each vendor (Microsoft, Dolby, MPEG, Xiph...) creates its own or copies it from another vendor.

Multichannel recordings are often referred to as "Surround".