Hi Michael,

This doesn't quite address the question directly, but I just wanted to
note something from my experience with triangular envelopes.  I use
linear triangular envelopes as a basis for most of what I do, mostly
on the single note level and not at the phrase.  I've found that the
duration of notes or the scale of ideas deeply affects the experience
of the triangle; if the duration is shorter, the slope of the triangle
is steeper, and if the duration is longer, the slope is more gradual,
given that the start and peak values are the same.

Perhaps obvious, but it was something that affected how I worked with
triangular enveloped sounds and has become a very important quality to
me.  I did experiment with half-sine's and various other shapes as
well but eventually settled on the linear triangular envelope.  I
think keeping in mind the slope and that if you're working with
something that is duration dependent might help to guide finding the
shape that will satisfy your ear.

Hope that helps!
steven



On 3/1/06, Michael Mossey <mpm@alumni.caltech.edu> wrote:
> This is a question about computer-assisted composition.
>
> I'm playing with expressive percussion shapes... i.e., beating on a drum
> in a regular rhythm, and computing a phrase shape with a beginning and
> middle and end. Perhaps starting quiet, getting loud, then quiet again.
> Perhaps starting slow tempo, then speeding up, then slowing down.
>
> For example, consider a soft-loud-soft shape. I programmed the amplitudes
> as a sinusoidal curve moving from trough to trough. (The curve expressing
> the amplitude in db) So how did this sound, subjectively? It wasn't
> completely satisfying.. the very rounded top came sounding like the shape
> had gotten a bit static during the middle part.
>
> Then I programmed a simple straight line upwards to the middle of the
> phrase, and a straight line down. (again straight on a logarithmic scale).
> Sounded a little more compelling. Then I modified it to peak such that the
> first half length and second half were in the golden ratio. Pretty nice.
>
> Still a little oversimplified sounding since the crescendo and sudden
> switch to descrescendo were obvious.
>
> Anyone have ideas for other curves?
>
> Mike
>
> --
> Send bugs reports to this list.
> To unsubscribe, send email to csound-unsubscribe@lists.bath.ac.uk
>