[zahlman]

If I feed a 7hz input to some cheap hand-made thing like https://www.youtube.com/watch?v=liSEwqdq7aA , will it not vibrate at 7hz and thus produce a 7hz "tone" (disregarding that humans won't perceive that as sound, at least not the fundamental)?

[jasonwatkinspdx]

No, because reproducing the fundamental is the thing. Saying otherwise is kinda like me saying I'm gonna take a voice call, run it through a filter that generates a ton of distortion harmonics, then seperate out those distortion harmonics, and then call it a "tone" of your voice.

But also the original post was about a 7hz tone somehow resonating with a chicken's skull cavity, which if you know the basic wave equation relating wavelength with frequency is an absurdity. The waves involved are multiple orders of magnitude too big to couple to a volume that small. They'll just diffract around like nothing.