On Wed, 2007-08-01 at 23:49 +0100, john henry dale wrote: > 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 > 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 ?
You can (should) be able to use "distance" and "height" to do what you need to. "distance" is the distance between the listener and the moving object - it can be a 3d list provided that path-3d is "t", such as '(0 1 0)(0 2 3)), etc, where each sublist is an x/y/z triple. Same for height. > 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 ? I think this is still valid, there's some details there (and I think there's a dlocsig.html file in the clm distro as well): http://ccrma.stanford.edu/~nando/clm/dlocsig/ Basically you specify angles (azimut and elevation) for the speakers and then you have to group them in triads for 3d (ie: you have to tesselate(sp?) space so that it is covered with three adjacent speaker groups - I gave up on finding lisp code that would do that automatically). There are some default configurations in the source file that should provide a guide. > 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 ? They sounded, well, like spiral paths :-) That does not necessarily mean they make good musical sense, of course... Sometimes I did use gnuplot to visualize them, there's some functions in the code to drive gnuplot but I have not tested the whole thing in a long time, I don't know if all that code still works. > Also, would i also need to render my final output as an Ambisonics > file for 9 speakers to accomplish something like this ? You choose your rendering model. No need to use Ambisonics. The advantage of it being that you could render to an Ambisonics B format 4 channel soundfile and then decode that at "listening time" for any array of speakers with the proper decoder. > Sorry for the heavy question-load, but I'm getting a little lost in > all this 3-d spatialization stuff. It is complicated... -- Fernando _______________________________________________ Cmdist mailing list [email protected] http://ccrma-mail.stanford.edu/mailman/listinfo/cmdist
