I Have an Idea for a Musical Instrument

But... It will not be a lucrative commercial product; too big, too expensive to build, too small of a market.

But... I believe it's something that could attract eyes and attention, maybe in the "maker" community or woodworkers, or recording studio groups.

Any ideas on the best way to monetize this?

Your best bet would be to look for investors, keep it safe though and sign a NDA with everyone you talk about this