Surround panning with pictslider with a twist

Mar 19, 2012 at 3:56pm

Surround panning with pictslider with a twist

Hi All.
I wondered if someone could point me in the right direction (literally).
I’m putting together an installation utilising 5.1, controlling the panning with a pict slider (?)
The idea is that folks get to hear the on-stage sound of a band, on stage, from each of the players’ listening perspectives; so they move the pictslider to various points which signify the position of each player.
Also, they can put themselves in the audience and listen to the front-of-house mix.

The surround array will reflect the direct/ambient sound from each of the participant’s listening perspective so, for example, when they are stood by the keyboard player, they will hear his foldback, together with the ambient sound in the venue. When they are in the audience, they will hear room reverb in the Ls and Rs, along with crowd noise, and a FOH mix in the LCR.

I’m struggling to come up with an idea to decode the pictslider’s outputs in order to reflect the desired sound. Any clues would be extremely gratefully received!! Is it even possible using the pict slider?

Mar 19, 2012 at 7:02pm

first of all, divide up the problem into two parts: first program the DSP, then build the interface.

with pictslider it should be possible, yet not perfect, because it is not round, and
you might have to decide to use it skipped for 45 degrees (i.e. left front is in the middle)

or try to limit the picture slider to a circular movement, using [clip] and a “set” message to
itself behind its outputs.

Mar 19, 2012 at 9:13pm

Hi, many thanks for the response. I need to ask as to why it would be better if circular? The ‘real’ area the pictslider will represent will be a stage and a hall, both oblong.

Mar 20, 2012 at 12:49am

an imaginary room might be a rect, but the positioning (panning between LF RF LB RB) will
happen in degrees at a – yet – unknown distance to the ears (i suppose you want the
imaginary listener to be in the middle of the room.)

if a signal (the virtual drummer) will be in a corner of the room, that will still be a
panning position of LF which is -45° on the GUI, just more far away than something
at -90°.

if you really want to build a DSP code for free positioning in a sqared room, with
first reflections and filtering and all these things which will be required for that,
you would of course also have a square shaped GUI object for that.

but a circle will still be involved into the required calculations (audio- and control-wise)
anway, and i strongly recommend to start with that. :)


Mar 20, 2012 at 12:59am

or the other way round:

if you would build your audio effect based on the fact that there is (eventually) an 1:1 relation
between your speaker setup (which is a sqare) and the imaginary room (which could also be a
sqare) it will quite easy to position virtual sound sources around the walls of the room – but
extremly complicated if not impossible to calculate any other position in the virtual room.

it will also be almost impossible to calculate the gain reduction which is required when a
virtual sound source is the left top corner of the room (-45° if it is a square), and you _must
reduce the gain of the channel LF to get the right effect.

so in my opinion you _must start with the position-by-angel thing and that suggest to have
a GUI which at least includes a circle. :)


Mar 20, 2012 at 11:07am

Got it. However, I think I’m going to simplify drastically! I’ll set up some spots which the participant can select, and have them trigger the sends to the loudspeaker array. Yup, I’m whipming out, but I’m on a deadline. Many thanks for your time.


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