I worked on the Dead's stage crew for awhile.They were running around 70,000 watts.Phil lesh was playing bass through 48, 18in John Meyers speakers.The system was capable of holographic effects and that made an entire stadium resonate like a drum shell.Lesh worked with subsonics quite a bit too.Some deadheads do seem to strike people as having had their brains turned to mush. the continental plates cracking down the center to the core of the earth. :) With a monster PA and sub system, I could crack skulls and turn brains to mush with these frequencies. I'd like to loop a 30hz frequency at 10,000 watts through 10 subs loaded with 18 inch bomb simulation speakers. It would be like a 10 kilometer alien ship landing on the stage. Massive.