I have been trying to figure out the acoustical resonant frequency of objects. I think their are engineering formulas that could be used. For example if you have a 1x1x1inch block square of iron, at what acousticaly resonant frequency would it be tuned to? I imagine the shape would have something to do with it. For example if the iron block were a 1x1x1inch sphere, at what acoustical resonant frequency would it be tuned to? A tuning fork was designed to resonate at specific frequency of sound via the inherent physical properties its design contains. You can slap it and the tuning fork will produce the frequency of sound. Lets say the sound at the same frequency was produced via other method and directed at the tuned fork. Would it vibrate because the freq. is resonant to its own shape?