Roman Haefeli wrote:
hi rodrigo
afaik, the number of speakers for an ambisonic installation doesn't matter, since you first compute an ambisonic sound in the B-Format, which has always 4 channels, iirc. once you have the b-format computed,
yawn...who still uses the b-format nowadays? b-format is just a very small subset of ambisonics (otoh, when you are stick to 8 channels b-format will be the best you get...)
you can use it for several configurations of loudspeakers, but you'll have to measure the position of each loudspeaker and then compute the signal for each speaker accordingly.
i don't know the cubemixer of iem, but the website (http://iem.at/projekte/acoustic/awt/abcde/project_view) says:
"Dabei wird nach dem ambisonic-Prinzip eine mehrkanalige lautsprecherunabhÀngige ReprÀsentation eines periphonen Schallfeldes generiert (Encodierung), und diese anschlieÃend ÃŒber ein bestimmtes Lautsprechersetting (Hemisphere) wiedergegeben (Decodierung)."
for me it sounds that you can use the cubemixer to compute ambisoncics b-format (encoding). so you could do the decoding afterwards for your special configuration, which has 8 instead of 16 speakers.
yes, that is what ambisonics is all about.
basically you should have a look at the decoder~ on the DSP-side. iirc, somewhere it should read in a matrix (or something similar) of loudspeaker positions: adapt that to your needs.
additionally you will also have to reduce the ambisonics order to 1st order only (which is b-format) since the number of loudspeakers must be
= the number of ambisonic channels which are (n+1)² (with n being the
order)
hopefully i'll have more time to answer your question better next week.
mfg.asd.r IOhannes