A long time ago, when I was still in school in Toronto, I became fascinated with an obscure form of surround sound recording known as Ambisonics. In researching a paper for school I became smitten by the approach conceived by English mathematician Michael Gerzon. It’s a truly elegant system, something beyond the commercially successful surround sound approaches that we all know.
I was especially impressed with the Cowboys Junkies 1988 album, The Trinity Session. It was recorded in a old church on King Street in Toronto, in a single day. The band played in this place with incredible acoustics, ringed around a single Calrec Soundfield microphone. The Soundfield microphone is the surround microphone design based upon the theory originally published by Michael Gerzon at Oxford University.
The trouble is that beyond the basics, Ambisoncs becomes very deep and mathematical. That makes it difficult to share my enthusiasm for the technology with others. Nonetheless, that enthusiasm keeps me reading the excellent SurSound Mailing List run by Virginia Tech. That list includes some of the finest and most experienced minds in audio, including some of the folks who wrote the very text books I used when I was in school.
It was there that I recently encountered a very interesting thread. This thread referenced some AES documents that are not freely available to the public. It also included a link to an excellent presentation by Rozenn Nicol of Research & Development at Orange in France.
This document is the most straightforward introduction to various advanced surround sound systems that I’ve ever encountered. While this PDF of 45 slides is purely introductory, it touches on everything from stereo theory, high-order Ambisonics (HOA)and wave front synthesis (WFS), without being overly mathematical. Highly recommended!