Looks really neat. I wish I had one, I am curious but it just sounds like an FM to me. In the demos I hear very decayed percussive FM sounds or mellow bell like FM sounds.

It looks most similar to a Rhodes piano-type electromechanical keyboard, where tuned metal elements are somehow actuated and then sonified with a guitar pickup. Unlikely theres any FM which would require independently digitizing each of the resonators and just generally a lot of complexity that doesnt seem warranted.

The similarity in timbre isn't coincidental though -- FM is noted for its ability to emulate complex timbres like bells/metallic tones (such as electric pianos) that are challenging for more traditional subtractive synthesis architectures.

Yeah as far as I can tell the bars are just producing sine waves and everything else is done within the electronics, interesting concept but honestly not all that exciting to me.

If I understand correctly, it is doing frequency modulation somewhere, but the main point is that you can physically interact with the resonators, and influence the sound that way.