Topic: TetraMic Ambisonic Mic: How Does It Work?

[Len Moskowitz (Core Sound)]

I thought the proper ambesonic playback setup was a tetra speaker array setup just like the capsules

If the capsules were "directly" connected to speakers, it would be the way to go. But the capsules signals are converted to B-Format (the capsules direct signal is A-Format) which allow to feed any speaker setup.

A common misconception is that a Tetrahedral Ambisonic mic is really four common cardioid mics, and the four raw mic feeds can be used for playback, just like you'd use four cardioid mic tracks.

Not!

A better way to think of it: An Ambisonic mic is an acoustic measurement tool.  It measures everything that's happening acoustically at the center point of the tetrahedron.  That acoustic information happens to be captured in four tracks that a processor (typically a computer or a dedicated device) *must* analyze.  The processor then synthesizes (i.e., models) as many essentially perfect microphones at that point in space, each with any arbitrary pickup pattern and pointed in any arbitrary direction.  That includes height information.

It also, completely independently, synthesizes and writes playback files (typically WAV or Wave-EX files) for playing back over as many speakers as you like, placed at arbitrary angles and (ideally) at arbitrary distances relative to the listening position.  So you can playback in mono, stereo, 5.1, 7.1 or pretty much any format you like.

Does that help?

Questions or comments to: moskowit@core-sound.com .  I'll post relevant info.