I protoboarded this circuit: http://www.popsci.com/diy/article/2008-04/build-pocket-theremin-cheap alas, it seems to make an extremely gravelly noise - the term "hoarse cat" came to mind. Anyways, what could be causing this? I think I have developed a general idea of how the circuit works, however, it does not explain this given that I simply used a proto board to hook up that exact circuit. I mean, could I have accidentally used a low-voltage 555 (if that does anything?) or, you know, whatever. I'm thinking my part tolerances are close enough (well, radioshack). Thanks! Oh yea... are my photocells supposed to be of very similiar values? I can get a slightly better sound out of it by using a bigger capacitor on chip '2'. Speaking of which, does anyone know any good (fairly) detailed explanations of the 555 timer? That little thing is ubiquitous. Oh, and uh, thanks a lot for any help.