Brown note

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This article is about the defecation-inducing sound. For the random signal, see Brownian noise. For the guitar tone, see Brown sound.

The brown note, according to an urban legend, is an infrasonic frequency that causes humans to lose control of their bowels due to resonance.

1 Terminology
2 Testing
3 In fiction
4 References

[edit] Terminology

The name is actually metonymy for a common color of feces. Effective frequencies are reportedly between 5 and 9 Hz, below the audible range for humans (generally humans cannot hear sounds below about 20 Hz), but supposedly in the range of resonance of human body parts. However, as the supposed effects are difficult to explain through known medical science and have yet to be verifiably reproduced in a controlled environment, most medical professionals are of the opinion that the brown note, at least as described in the legend, does not exist.

[edit] Testing

The note was tested on the television show MythBusters using Meyer Sound subwoofers on par in quantity and quality with those used at major rock concerts.^[1] The experimenters on the show tried a series of frequencies between 5 and 10 Hz at 120–160 dBSPL, but they were unsuccessful in producing the rumored effects. They all reported some physical anxiety and shortness of breath, even a small amount of nausea, but this was dismissed by the participants, noting that sound at that frequency and intensity moves air rapidly in and out of one's lungs.

Another show, Brainiac: Science Abuse, performed a similar experiment using 22.275 Hz at −30 dB (according to the show's producers used by Japan's Police and tested by the French Military). During the program, they broadcast the note over the air (and into the living rooms of viewers) in an attempt to cause bowel movements among those who had chosen to stay in the room despite repeated warnings and opportunities to leave. It should be noted, however, that no television speakers and very few subwoofers are able to accurately generate sound at this frequency at a significant volume. They also alleged to have confirmed the myth with a subject, but this subject was out of camera shot for all of the piece except at the very beginning. Using an audio editing software it can be seen that brown note doesn't exist anywhere in the soundtrack. Instead, they replaced it with a 91.8 Hz sine wave tone making it audible to the viewers, therefore not having any effect on one's bowels.^{[citation needed]}

In 2003, a team of researchers held a mass experiment where they exposed around 700 people to music laced with 17.5 Hz sine waves, produced by an extra-long stroke subwoofer mounted in the end of a sewer pipe. The experiment took place in the Purcell Room, London. The team was warned against the experiment by physicists (and a person in the local hi-fi store) who were concerned the audience would have to evacuate their bowels in the concert — but in this double-blind test of the effects of airborne infrasound, the team reported none of the legendary effects. There were many reports of anxiety in the audience — and of feelings of pressure on the chest. The team was interested in these extreme bass notes as they have been implicated as a possible explanation for ostensible hauntings.

Jürgen Altmann of the University of Dortmund, an expert on sonic weapons, says that there is no reliable evidence for nausea and vomiting caused by infrasound.^[2]

[edit] In fiction

The sound was featured in an episode of South Park (3x17: "World Wide Recorder Concert") as a sound that caused the entire population of Earth to empty their bowels uncontrollably. In the show, the "brown noise" was described as "92 cents below the lowest octave of E-Flat", though the sound was actually the F# musical note (46.25 Hz). Interestingly, the wavelength of this note is 746 cm (24.5 ft), which is roughly equivalent to the length of the small intestine.^[3]