8 Channel Surround Panner

shofarsogood · Post by **shofarsogood** » 11 Dec 2013 21:43

I thought this was possible in Lemur but now I'm not so sure...

The situation: doctoral dissertation using 8 independent mono channels of audio. The audio is NOT 5.1 or 7.1 since those are forward-biased formats with more speakers towards the front of the listening area because these formats were designed for film. My project considers all directions equally so the speakers are spaced equally around a ring - one speaker every 45 degrees.

The Need: to be able to adjust the volume (panning) of all 8 channels simultaneously using a joystick type of interface for a test subject. This means that one "ball" (in Lemur parlance) sends appropriate continuous controller variables for 8 simultaneous different continuous controllers (which eventually control the volume coming from each of the 8 speakers) so that the sound can be moved around the circular playing field and left at a certain point determined by the user. Basically, the close the ball is to an onscreen virtual speaker, the louder the sound should be from that real speaker.

Since the speakers are in a ring, the onscreen interface must look like circle which takes out the Multiball tool. RingArea starts with the circular interface but appears that the attraction function can not be turned off adequately. For both of these there is the added issue that I am not looking for an "X-Y" controller because that is only 2 dimensions. I would like to control 8 dimensions with one ball.

I looked around the User Library and also did several searches for surround panners but not much luck. Can this even be done in Lemur with some fancy under-the-hood programming?

Dave

midimockup · Post by **midimockup** » 12 Dec 2013 01:40

Fascinating!
Yes, sure can! You just need to script x/y to send multiple cc values. Lemur can handle quite complex mathematical functions quite readily, and a single ball can send multiple values.

But then I see that you want to control 8 dimensions while the multiball is fundamentally a 2 dimensional object--- so I'm not sure how you derive the rest. I'm assuming you have some mathematical formula that specifies the relationships. The only other dimension to the multiball is Z, and that is only an on/off state (pressed, or not pressed). However, you could get additional variables like color. You could also have toggle buttons that change the output of the multiball.

If you needed to manipulate MIDI data in true 3D space you might rather team up with a Leap Motion developer.

Without knowing the specifics I can't be of much more help I'm afraid.

HTH,
MOH

Edit: Oh I see that you want it to look like a ring. Well you could limit the boundaries of the multiball. How you make it "look" like a ring I'm not sure. There are other developers that are better at the graphic design elements of Lemur than I. Usually people do it by clumping together lots of text objects.

Edit2: With the ring object you can "fake" turning off attraction by having an OnFrame script and simply having the ring "hold" the last pressed coordinates.

Post by **Macciza** » 12 Dec 2013 13:38

Hi
Yep I would say it is doable.

There are various ways to deal with the attraction point issue depending on whether and how you might want to use it . .
The next thing is how you want to deal with the x,y data you are getting back from the RingArea - polar is probably best, there are some building functions to help you out there
You are really only working in 2 dimensions, not 8; You can convert the x,y the angle and distance and then use that to do the control of laceration and volume
Depending on how you want the system to respond you could also come up with different volume mapping options i.e. centre could be equal vol all speakers or silence . . .

Pretty sure there is an old Surround project that probably does what you want , or only need a minor edit . .
Cheers

shofarsogood · Post by **shofarsogood** » 20 Dec 2013 13:16

Noob question:

Is there a way to turn the attraction completely OFF in the ring area object? Or, a way to make a round multi ball object? Musician here, not a mathematician...

Dave · Post by **Dave** » 28 Dec 2013 08:43

You will need some high school mathematics. If you use a multiball then you can calculate the positions of the virtual speakers using trigonometry. I'm not sure how to display them but possibly by using some transparency. You will also need to use trigonometry to calculate the distance of the ball(s) from each of the eight virtual speakers. At some suitable frequency sample these distances, display them as faders in Lemur and output the inverse of these values as a set of 8 control changes which you can map to 8 faders in your DAW. One fader per track, one track per speaker. Dave.

shofarsogood · Post by **shofarsogood** » 02 Jan 2014 22:12

Dave,

I tried what you are saying which is essentially a linear relationship distance from speaker to MIDI volume. It doesn't work for the same reason that pan pots on a mixing board are not linear - you get a "hole in the middle" effect where panning to the center is softer than panning either hard right or left. Mixing board pan pots use a sine curve so that the center position is not halfway down but .707 down the curve.

I've implemented the sine curves and have a rudimentary 8 channel panner working but it needs some tweeking. The methods I used were not pretty and I'm sure there are some really smart people who could make a much better implementation, but I'm a musician, and the last math I took was about 40 years ago! Maybe I'll upload it to the user library when I get finished if people promise not to laugh...

Softcore · Post by **Softcore** » 02 Jan 2014 22:22

Each uploader, including myself, has a lot of stuff to laugh at - mainly his own older creations.....so no need to worry about that!

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