I have recently subsrcibed to the surround-sound discussion list, and this
carries a lot of expert information about what is clearly a complex and rapidly
developing field. A good starting point is Dave Malham's 3d-Ambisonics page: 
	http://www.york.ac.uk/inst/mustech/3d_audio/ambison.htm

which includes info on how to join the sursound list.

Richard Dobson