I use a metal body (let's say cooking pot) in which I induce eddy current via induction at certain frequency which I can change as I wish.
Every object has it's own accustic resonant frequency. If exciting frequency is the same as the accustic resonant frequency of the body, then the sound produced by eddy currents will also be strong at that frequency.
If I drive the coil at half the frequency (or 1/4th the frequency) of an accustic resonance of the cooking pot), then the sound will still be loud at the resonant frequency.
But does the same effect happen if I drive it with double frequency of the cooking pot accustic resonant frequency? Do I still hear loud frequency at the accustic resonant frequency, or does this only apply if the exciting frequency is lower(half, one fourth...) of the accustic resonant frequency?