# [PD] Re: multi-speaker panning.. problamtic maths

alexandre r. decoupigny alex.decoupigny at gmail.com
Wed Oct 25 11:07:08 CEST 2006

```hola,

first of all.. thank you all so much for your support. it is great
to have input from you.

i finished a first sketch. i am not using the vbap, but use objects form the
nSlam 1.0 and the the xjimmies library. i found some objects there that are
workable for me. however there remains the difficultiy that derek mentioned
with vbap, which
is that there is some sort of gap occuring in the panning process.. this i
can decrease with a parameter from e.g.
an [opan2~] object (eight speaker panning object) that lets you set the
fadetime in miliseconds. still it is not that satisfactory if i pan from
left to right.. circular motion is good. this is due to to frank's (who took
me step by step, for which im supergrateful because it made me understad
what im actually doing) and iohannes input. i combined the two approaches.
you can see this in the example patch that is attached to this email. to run
it you need the xjimmies library, which you can get at
http://tot.sat.qc.ca/eng/nslam.html. <http://tot.sat.qc.ca/eng/nslam.html>
in the patch there is also a feature that allows to record movement in
space. so the idea develops into that of an
instrument that allows you to play with sound in space using
a simple usb-joystick.

however there remain a lot of issues, like the ones that mathieu discusses
(thanks for explaining !).

first i dont know what the r is in the following:
"However, I believe that it's energy that should be r^-2, therefore
amplitude should be r^-1. That's assuming ideal 3-D dispersion (no
ceilings and no walls). Is that right?"

then i obviously still face some problems in the sketch:
for example that the way it is set up, the patch only reacts
if there is movement on both axis.. for example if i put
the joystick all the way to the front and move it from left
to right, nothing happens.. no idea how to deal with it..

right now i hope to use more of the parameters offered by
the xjimmies library for their panning objects: seperation and
fade time and later maybe find better ways to deal with the
x and y outputs of the joystick.. i would also love to make
it more dynamic, which takes me back to mathieus points.
i just dont seem to have knowledge in maths to be able to to follow mathieus
explanation : )

more hopefully soon and it would be great if you have any ideas. of course
this means everybody as well.

best

alexandre
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