So I came up with the following setup. I took a speaker, I placed a thin foil of plastic on top of that speaker, and then I added tiny little crystals on top of that speaker.
Aşa că mi-am imaginat următorul aranjament: am luat o boxă şi am pus o foiţă subţire de plastic pe ea, apoi am adăugat cristale micuţe deasupra.