This is nothing fancy (however perhaps entertaining), simply supplying enough power (volts + current) to a speaker to make it move at very low (inaudible) frequencies.

In this case, I'm using a computer to generate "sub-bass" frequencies and pumping them through a Yamaha P3200 power amp running at 4 Ohms, 520 Watts to a Cadence 15" car audio-class subwoofer. The volume is turned up and down a few times for each frequency.

Note how at 3 Hz and particularly 1 Hz, the dropoff in performance is noted; the sound is still seen, but presumably the efficiency is quite low at this point and a lot of energy is required to make the speaker move. My neighbours would not be impressed, but I suspect these frequencies are too low and low-powered to carry through my walls.