[CM] translating spirals into music CLM

[john henry dale]

Hi Fernando,
in taking a look at dlocsig.html, I found what seems to be a way to generate
spiralling sound spatialization using Geometric Paths (
dlocsig.html#geometric-paths):
*make-spiral-path* &optional-key
(*start-angle* 0d0)
(*total-angle* nil)
(*step-angle* (/
dlocsig-one-turn<file:///Applications/CM.app/Contents/Resources/clm-3/dlocsig.html#dlocsig-one-turn>100))
(*turns* nil)
(*distance* '(0 10 1 10))
(*height* '(0 0 1 0))
(*velocity* '(0 1 1 1))
But i'm not sure where in my CLM composition's code I would insert this
spiral path info to actually apply this spatialization to my output track.
For my performance the audience will be surrounded by 9 speakers ( 4 on the
floor, 4 at slightly above ear level when sitting + one speaker above) , so
basically a cube of about 25x 25 x 5 feet  with a speaker at each corner and
a tweeter tree overhead. I'm trying to figure out two things in this email:


1) What arguments do i give the make-spiral-path function to generate a
logarithmic spiral which goes upward into a cone which would come to its
apex at the height of the audience's ears (about 5 feet 5 inches) with a
total angle of 23.5 degrees ?

Basically i am trying to mimic the spiral created by the Earth's
precessional cycle on a small scale for my final performance. This might be
easier with a visual aid. Check this movie out:
http://www.lunarplanner.com/HCmovies/HCmovie300Frame.html. So using this
movie as a model, the height of the spiral at its apex (and at the climax
point of the composition) would be, figuratively, in the center of the earth
where the two cones formed by earth's 23.5 degree wobble on its axis come
together at one point. Does that make sense ?


2) What arguments do I give the arrange-speaker functions to, i.e. how would
I map this speaker arrangement ?

What were your results in testing these spiral paths on a multi-speaker
system ? Did you use gnuplot to generate your spiral coordinates or can you
fairly easily plug them into the make-spiral-path argument ?  Also,  would i
also need to render my final output as an Ambisonics file for 9 speakers to
accomplish something like this ?
Sorry for the heavy question-load, but I'm getting a little lost in all this
3-d spatialization stuff.

Best,
John Henry Dale
MSc Digital Composition and Performance
University of Edinburgh, 2007

ps- If making this spiral-path requires outputting as an ambisonics b-format
file,  do i need dedicated Ambisonics hardware to accomplish this or can I
output this file with software through a DAW like Pro-Tools ?
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