Ambisonics

VVAudio's software uses ambisonic principles for surround sound processing. Ambisonics is a method of recording and reproducing surround sound that was originally developed in the 1970s, mostly by Michael Gerzon. For more information about ambisonics in general, the Wikipedia article on Ambisonics is a good place to start. Here are a few important ambisonic terms:

A-Format – a recording where each channel corresponds directly to one capsule in the microphone array. For TetraMic these signals are Left Front Up, Right Front Down, Left Back Down and Right Back Up.

B-Format – a general purpose representation of the soundfield based on spherical harmonics. For 1st order, as used here, this consists of one omni and three figure eight pattern signals called W, X, Y and Z.

AMB File – a specific file format for B-Format material, based on Microsoft’s WaveFormatExtensible. For a definition go to http://members.tripod.com/martin_leese/Ambisonic/B-Format_file_format.html

Speaker Feeds – signals that correspond directly to the speakers in the targeted layout, e.g. stereo, hexagon, or 5.1. Speaker signals are required for some distribution media like CD’s and DVD’s, as well as being used to listen to.

Interleaved vs. Multi-Mono – an interleaved file combines multiple channels into a single file. If not interleaved, surround sound will usually be represented by several ‘.wav’ files, each a mono, or single channel file. A combination, where a pair of stereo files are used to carry four channels can also be read by VVMic.