Okay, so for my birthday my brother got me a couple of these things called Mighty Boom Balls. They're a relatively low-end (in the monetary sense) vibration speaker i.e. you attach them to a surface and the surface is transformed into a resonant speaker through vibration. So I thought it might be a fun experiment to try and build a decent resonator/pair of resonators to squeeze the maximum performance out of these things. There are however two mitigating factors. Firstly, I have very little money, so need to make them out of cheap, and preferably readily available, materials. Second, I have no idea what shape they should be, or if they should be hollow or solid. I attached one to an old guitar and that gave me the best effect so far, but I can't really use that.
So any ideas? I need tips on shape, size and material. Any other notes would of course be welcome.
Oh, and remember, I have 2 of these things, so I can attach them both to one surface, or to two separate ones. Would a combination of two different materials perhaps give a better sound quality? Hmm.