I went to ambisonic and read the FAQ. I do not agree
with them when they
say that 2-channel stereo is only good for imaging between the speakers.
It is possible by using phase differences (and the assumption that
people are not living in sound-dead laboratories) to project sounds
outside of the stereo-field.
I did not find anything either to support that 4-channel is superior to
7-channel ... Maybe I was not looking hard enough ??
if you really want to understand surround, i'd like to pass along a
pointer that jesse chappell gave me: Sound On Sound had a multipart
series on surround a few years ago. its really good, and covers
ambisonics as well as all the current commercial "standards" in some
depth. its not a textbook, but you will walk away, as i did, with a
much deeper understanding.
this will get you started:
http://www.soundonsound.com/sos/Aug01/articles/surroundsound1.asp?session=d…