morphazoid

Use headphones. Speakers can feed the room back into the microphone before the digital recursion does.

Input signalsilent
A fitted L-system tree whose branches vibrate as microphone audio travels through them.

Pythagorean Pine. Thirteen generations and 1,023 connected segments; 48 of 48 breadth first delayed descendant paths carry audible gain. Microphone loudness travels outward from the seed by vibrating the branches.