[PD] multi-speaker panning.. problamtic maths

derek holzer derek at x-i.net
Mon Oct 23 21:10:27 CEST 2006

Howdy all,

Georg Holzmann wrote:

> I would suggest you to use the vbap (vector based amplitude panning) 
> external, which does exactly what you are trying to achive ...

The VBAP objects are great, except for one thing that is inherent in all 
vector-based systems: try to pan a sound directly from left to right 
through the middle of the loudspeaker circle you have defined. At a 
certain point (exactly the middle), the sound will audibly "flip over" 
from one side of the sound field to the other. This is a result of 
making a radical shift in the radiant of this circle, which is the basis 
for all measurements in a vector-based panning system.

For four-channel panning, at least, I've been much more satisfied with a 
quad-panning system based on a chain of stereo panners, going from 
front/back to front:left/right and back:left/right. For a four channel 
system, and when you want the sound to move within the bounds of the 
phsyical speaker locations (as opposed to using a direct sound vs. 
reverberated sound system to simulate sounds outside the bounds of the 
speaker locations), this has given the best results for me. Otherwise, 
I'd love to see a better implementation of VBAP that accounts for this 
"hole in the middle" problem.


derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 132:
'Remember .those quiet evenings'

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