Re: On 8 speakers

Subject: Re: On 8 speakers
Date: Fri Jan 29 1999 - 04:50:57 EST

Chris continued:

>From: Chris Rolfe <>
>Subject: Re: On 8 speakers

>The diffusion controller is also interesting. In addition to specifying
>angle and magnitude (independent of speaker location), the user specifies a
>diffusion width, that is, send input 1 to all speakers between 0 degrees to
>90 degrees.
> x
> x | x
>x |__ x
> x x
> x

Is it possible to input this information in a kinetic fashion, such as
with a 'MIDI mixer console' (like the Mackie), so as to also take
advantage of the kinteic aspect of live projection?

Frequently, to 'draw out' an aspect of a sound, a 'pulsing technique' is
employed. (Easier to see than describe.) For example, imagine a sound
complex where there is a mid-frequency beating inside a complex,
transforming sound.

The fingers are on faders:

  Left 5 4 3 2 2 3 4 5 Right

and to highlight this aspect of the sound, fingers 3 and 4 of each hand
create small amplitude bursts (by moving up and down about 1-2 cm), in
time with the mid-frequency beating.

In terms of angle and magnitude, this may be difficult to explain in a
graphic, but easy to do in a kinetic sense. A code listing could look
something like: [Time runs from top to bottom (event list format), the
speakers are in columns, and the numbers represent (some arbitrary) level]

  SPEAKER (L) 5 4 3 2 2 3 4 5 (R)

                10 10 10 10 10 10 10 10
                10 12 12 10 10 12 12 10
                10 10 10 10 10 10 10 10
                10 12 12 10 10 12 12 10
                10 10 10 10 10 10 10 10

The finger movement 'pulsing' is refelected in the level shift from

While it might appear that such a subtle change (esp given that eight
speakers are up) might be difficult to perceive, it is my experience that
because the amplitude shifts are synchronous with a spectral change, they
are perceived quite clearly.

>I think the diffusion controller illustrates the limitations of a strict
>spatial model. What would be the xy equivalent of a 360 degree (diffusion)
>assign? If I had a global reverb return to the mixer I would assign it to
>all speakers, but by no means imply an xy position.

Possibly this would be an advantage of a mixer-based kinetic input as an
addition to the system.

> And aware that each decision might close down
>a valid sound-reinforcement technique.

Agreed! which is why I ask about having a MIDI-mixer interface in
addition to the graphic one. How difficult would it be to implement?



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