Dynamic Stochastic Synthesis and Perlin Noise … what’s the diff?

Perlin noise was used to generate this Ribbon, by Anthony Mattox

Its just struck me that Xenakis’ Dynamic Stochastic Synthesis may be very similar to Perlin Noise!

Just the same as Perlin Noise is used by digital graphics artist to introduce a ‘world-like’ turbulence to graphical textures … I’m wondering if Dynamic Stochastic Synthesis is not very similar in that Xenakis recognised that the ear needs a minimum amount of complexity to make a sound be perceived as real … and introducing ‘noise’ into a texture was a means of doing that:

it seems that the transient part of the sound is far more important than the permanent part in timbre recognition and in music in general. . . . The intelligent ear is infinitely demanding, and its voracity for information is far from having been satisfied. This problem of a considerable amount of calculations is comparable to the 19th- century classical mechanics problem that led to the kinetic gas theory. (Xenakis. Formalized music : thought and mathematics in composition. 1992, p. 244)

and …

We can start from a disorder concept and then introduce means that would increase or reduce it . . . We can imagine the pressure variations produced by a particle capriciously moving around equilibrium positions along the pressure ordinate in a non- deterministic way. (Xenakis. Formalized music : thought and mathematics in composition. 1992, p. 246)

Note: I came across these quotes in an excellent paper by Sergio Luque entitled “Stochastic Synthesis: Origins and Extensions”

The interesting thing about Perlin Noise is that is uses different levels of noise at different frequencies. Different effects can be achieved by modulating the amount of noise created at different frequencies. A lot of Xenakis’ thinking was along the same lines … in the sense that he considered order at different scales. In the graphics world, low frequency noise is mountains and high frequency noise is rocks … so different frequencies can be considered as different scales.

I havn’t quite understood, given the descriptions of Stochastic Synthesis, if there is a ‘frequency’ dependent modulation in it. If there is, then as far as I can tell it is practically the same as Perlin Noise.

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