The second season of MythBusters premiered Wednesday night on Discovery Channel. Sometime this season, the MythBusters team will test the existence of the Brown Note.
If you've never seen South Park episode 317, the Brown Note is (allegedly) a low frequency vibration which, when reproduced at sufficient volume, resonates with the depths of the human digestive tract to cause what medical personnel call "involuntary gastrointestinal motility." Put in less technical terms, the Brown Note reputedly precipitates a loss of sphincter control, giving rise to immediate defecation.
Host Adam Savage stood in the middle of a subwoofer ring, where he experienced the effect of very low frequency sounds (down to 5 Hz) at extremely high levels (120 dB SPL with a 9 Hz sine wave, up to 153 dB peak with narrow-band noise), though the higher levels were possible only above 20 Hz. Additional protection for those working in close proximity to the subwoofer stack was provided by a box of extra-large Depends.
If this test proves successful, iTunes should consider selling an mp3 of the Brown Note to help people (Jon) who suffer from constipation.