[LAU] ambisonics: fons ambdec and muse.demon.co.uk ambidec

[Arnold Krille]

On Friday 07 January 2011 09:10:41 Giso Grimm wrote:
> On 01/07/2011 12:33 AM, fons at kokkinizita.net wrote:
> > Azim and elev are in radians, to convert to degrees multiply by
> > 180/pi. Note that for all layouts on the demon page, dist will
> > be 1 for all speakers. For ambdec you should use the real distance.
> 
> in ambdec, is the distance used for anything else then delay and gain
> compensation? Is it correct that for regular setups this does not matter?

I imagine it could be used:
Ambisonic when shipped seems to be normalized to distance of 1 unit.
When your speaker array is much bigger or smaller, one could use that 
information to rescale the sound reproduction.
But I haven't actually thought about this or even tried some formulas... Might 
not work.

One other usage for the distance is for near-field compensation. I believe 
fons' ambidec can do that, but isn't using the distance for this. Might be 
interesting to make the amount of near-field compensation depend on the 
distance of the speakers.

Finally, one of the main advantages of ambisonics compared to that 5.1/7.1-
crap is that your setup doesn't have to be perfect. Different distances and 
even different irregularities in shape can be compensated and still reproduce 
the signal as intended.

Have fun,

Arnold, just realizing that my "worlds smallest amb-rig" won't be finished in 
time for a lac-talk...
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