Certain low frequency sounds will make you hallucinate.
Dunno the exact reason offhand but probably can guess.
I once used 4" pvc to make a single pipe, pipe organ that resonated on that frequency.
Made everyone around crazy (except me, I knew about it and ignored the crazy stuff).
I think it's 14 hz that resonates best with the human gut and causes spastic evacuation.
I would never build anything like that.... more than once.
/johnny