thanks!
the wheels are made out of a special plastic, iglidur® J4. I turned them between centers to avoid any off-centric rotation. The angle of each wheel can be moved with a leveler for precise adjustment and control. Yes, I used cotton to hold the rosin. Then there are multiturn potentiometers for speed, which is overkill. For finetuning i got from broken violins the lower fine tuners.
As resonators, the piece uses a bass recorder, disassembled in its part and attached with a membrane.
Suprising was the damper clips on the strings. They act as a lowpass filter but amplifie frequencies based where on the string they are attached.
The piece is very close to Eliane Radigue older ARP2500 works but without electronics.
I can upload the audio ones I got the recording from the festival.