[openal] AL_SOFT_source_spatialize proposal

[Chris Robinson]

On 05/06/2017 06:25 PM, Lubomir I. Ivanov wrote:
> i guess it becomes a question if one wants to amend in terms of
> perceived loudness or in terms of precision.
> from what i've seen on consoles and DAW mixers used by engineers the
> multiplier is strictly 1/N.
>
> for such a bus it's crucial to amend by the precise multiplier as
> there is also observation of magnitude meters involved.
>
> for "ambisonics" and things like that sqrt(1/N) does a better job,
> they say. but this will clip more as more channels are added, thus i
> would probably go with: 1 - sqrt(1/N).

"1 - sqrt(1/N)" would go the wrong way. Downmixing stereo would have a 
gain correction of 0.29289 (less than 1/N = 0.5), quad would be 0.5 
(greater than 1/N = 0.25), etc. Keep in mind too that with real-time 
game audio, the global volume is likely to be reduced to help avoid 
clipping from mixing multiple sound effects and audio tracks, as well as 
distance attenuation reducing the volume of individual spatialized sources.

I'm fine with using 1/N if that's the consensus, though. I've currently 
modified OpenAL Soft to do just that. Any other questions or comments 
from anyone?