[LAD] Attenuation of sounds in 3D space

[Jörn Nettingsmeier]

john,

On 07/29/2010 02:35 PM, JohnLM wrote:
> On 2010.07.28. 22:06, fons at kokkinizita.net wrote:
>
>> Compared to conventional 5.1 pairwise panning the result will be
>> more even, without emphasising the speaker locations as would be
>> the case otherwise. In other words, the sound will be much less
>> seem to originate in the speakers.
>
> I stumbled on your own AMB-Plugins. :)
> They seem to do pretty much what I need. Mono->B-Format panner provides
> only angle controls.

yes. panning is only concerned with angle of incidence, whether in 
ambisonics, VBAP, or pair-wise stereo.

> So from what I can understand, if I apply doppler effect, distance
> attenuation and other pre-process filters to a mono input and then push
> it through the panner plugin I get fairly correct representation of
> sound in 3D space. Right?

depending on what you mean by "fairly correct", "representation", and 
"3D space" :-D

doppler would come into play only if you change the distance of the 
sound, not when you move it on the sphere, as the distance remains constant.

when you hand-craft distance cues, you should not expect wonders for 
sounds originating inside your sphere of speakers. travelling through 
the center quickly can be made to work, though.

> I failed to find anything discussing mixing in AMB. Can I just sum the
> channels of all sounds, like I would do it to any
> "direct-speaker-to-channel" formats?

yes. that's a fundamental property of all linear systems, and 
independent of the signal representation.

i've written a little howto for ambi mixing in ardour a while ago, maybe 
you'll find it useful:
http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html
for lac2010, i tried to find out how ambisonic mixing can be applied to 
a pop production:
http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Report-A_Pop_production_in_Ambisonics.pdf

best,

jörn