I don't know if this has been addressed before but how do they transmit sound through fiber optic cables, which only work well with light. Or is it an optical pickup? Or is the dieselharp just a joke?
Hmm, I may not have read the guy's description of his instrument very well, but it seemed like he was saying they transmit the sound from the guitar to a water tank through fiber optic cable without converting it into a signal first. The site you posted looks like something you'd use for a stereo with a digital optical output, which would make more sense. I'm pretty sure I'm missing something here...