Thread: Ambisonic IR
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Old 05-25-2021, 11:02 AM   #3
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Originally Posted by Kewl View Post
If a "true stereo" IR reverb is four IRs (2*2 matrix), a "true 1st order" IR reverb would be 16 IRs (4*4 matrix). It's been on my "to experiment list" for the past ten years...
Would it not simply be 16 independent IR processes for first order and not 16 different channels in the IR itself? Or wouldn't it actually be 12 since the W channel doesn't need to be convolved independently for each axis but rather as a matrix of the x/y/z signals? A stereo impulse is still only 2 channels, the true stereo part is to convolve the left channel and right channel independently through that stereo impulse. This is then mixed from the the now 4 channel result back down to stereo. I was just thinking, when I take an impulse with my first order mic I don't need to do it 4 times from 4 locations to get a true ambisonic IR. Perhaps that's what you meant all along though? I'm just trying to get it straight in my mind.

Anyways, for number 1 you do want to place the speaker at the location you want the emitter at and the mic in the spot you want the listener to be located. In my understanding, if you move that emitter around the listener it will be like rotating the entire room as you can't virtually move that speaker after the fact.

However...Zylia just did a very interesting demo of synthesizing multiple ambisonic recording positions in a room. I assume the same idea could be used to synthesize multiple ambisonic IRs, especially since they used wwise and unity to do it. That is my answer to question 2.

It is labor and processor intensive so make sure it's going to pay off in the end.
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