Click to enlarge.
During my exploration of DSP processes for muscle sounds I eventually realized I could make good use of the interesting Soundhack objects, which have been recently ported to Pd by Tom Erbe, William Brent and other developers (see Soundhack Externals).
Among the several modules now available in Pd, I focused my attention on [+bubbler] and [+pitchdelay].
The former is an efficient multi-purpose granulator, while the latter is a powerful pitch-shifting based delay, which allows a functional delay saturation along with octaves control; both work nicely in real time. More interestingly, performance testing showed that the max mean value (here referred to as a continuous event) produced by muscle contractions can be synchronously mapped to the feedback and loop depth of the [+pitchshift~] algorithm in order to obtain an immediately perceivable control over the sound processing.
Sound-gesture obtained through this mapping system are quite effective because the cause and effect interaction between performer’s gesture and sonic outcome is clear and transparent.
Here’s an audio sample. The perceived loudness of the sound and the amount of feedback is directly proportional to the amount of kinetic energy generated by the performer’s contractions.
I need to explore further this algorithm and understand further improvements for a real time performance.