I did another interesting experiment today. I used my Spica chaos electronic circuit and attached an electric buzzer to it. A buzzer mainly behaves like the oscillating relay in my VISPRE device. By tuning the chaos pattern and the current through the buzzer I could make it emitt snaring sounds with speech rhythms.
I could record and export some fairly good voices.
The setup is not the prototype of a working device, I see it more as a research project where I learned something from.
The buzzer is a mechanical device that is able to self oscillate because of positive feedback. If you excite it with random patterns mimicking speech in a way that self oscillation is short before to start, the tiniest energy fluctuation will kick in self oscillation with an exponentially rising signal ramp. In case of the buzzer it starts to snare.
It's this fragile state where pk modulation may control this transitional point of operation.
The second thing is an acoustical bandpass forming formants from the impulses. The voices I posted here still are sub optimum in terms of spectral composition. I am thinking of a set of tubes with different lengths and volumes resonating on the base frequencies of the human pharynx.