[LAU] ambiophonics vs. ambisonics?

[Jörn Nettingsmeier]

On 02/26/2010 06:42 AM, Bearcat M. Sandor wrote:

> It's ambiophonics that i'm interested in. Am i correct in my
> understanding, that nothing can be utilized by ambisonic processing
> during playback if the source material is only stereo?

i don't understand.
if you mean "can i blow up a stereo signal to use my four speakers", the 
answer is yes.
if the question is "can i blow up a normal stereo signal to use my four 
speakers so that the result makes sense", the answer is a cautious 
"probably not". but the same applies to ambiophonics. if there is no 
surround information, you can't expect good results.

there are a few stereo recordings done in UHJ format (most by small UK 
classical label nimbus) that do indeed contain ambisonic content that 
can be decoded to 4 speakers with great results, but they are rare. 
nimbus is still in business, though, and they maintain their back catague.
i can mail you a track or two off-list if you're interested.

another interesting approach might be "super-stereo", a feature which 
some old hardware ambisonics decoders contained to make stereo sound 
more spectacular over 4 speakers. but i have never tried it - if you're 
interested, i can wade through my archive for the decoding matrix.

and there's an excellent MAG article about using 4 speakers for better 
stereo replay here: 
http://www.audiosignal.co.uk/Resources/Surround_sound_from_2-channel_stereo_A4.pdf
nothing to do with ambisonic decoding, though.

best,

jörn