I have to admit that things like this intrigue me, yet simultaneously arouse a degree of skepticism. I've seen stuff out there recently (for double bass in particular) like a brass rod which you put in your pocket or somewhere on your body, but not even in contact with the bass, and supposedly it enhanced the sound of the instrument. But the proof is (usually) in the pudding, and Chick Corea (RIP) apparently used the PhiTon resonators, as did some of the bassists who worked with him, and from what I heard, they did/do affect the sound. And I like to experiment, so here are my questions so far:
1) What do they cost (ballpark)?
2) Can you use the same resonator for multiple instruments, including double bass, electric bass, acoustic bass guitar, EUB or does each of these instruments need it's own resonator?