If your house actually has significant eigenfrequencies built in, I would think you could get those issues at many different fan frequencies, or even from other

If your house actually has significant eigenfrequencies built in, I would think you could get those issues at many different fan frequencies, or even from other sources of vibration, like a washing machine's dryer program. Or by watching a movie or listening to music. I would think someone with the right math skills would be able to build something like a base trap to absorb most of the energy in those frequency bands, though.