Brown note
Encyclopedia
The brown note is a theoretical infrasonic
frequency that would cause human
s to lose control of their bowels due to resonance
. There is no scientific
evidence
to support the claim that a "brown note" (transmitted through sound waves in air) exists.
The name is metonymy
for the color of human feces
. Frequencies supposedly involved are between 5 and 9 Hz
, which is below 20 Hz, the lower frequency limit of human hearing. High power sound waves below 20 Hz are felt in the body, not heard by the ear as sound. The only other vibrations titled with colors are the colors of noise
and blue note
s.
used twelve Meyer Sound 700-HP subwoofer
s—a model and quantity that has been employed for major rock concerts. Normal operating frequency range of the selected subwoofer model was 28 Hz to 150 Hz but the 12 enclosures at MythBusters had been specially modified for deeper bass extension. Roger Schwenke and John Meyer directed the Meyer Sound team in devising a special test rig that would produce very high sound levels at infrasonic frequencies. The subwoofers' tuning ports
were blocked and their input cards were altered. The modified cabinets were positioned in an open ring configuration: four stacks of three subwoofers each. Test signals were generated by a SIM 3 audio analyzer, with software modified to produce infrasonic tones. A Brüel & Kjær
sound level analyzer, fed with an attenuated signal from a model 4189 measurement microphone, displayed and recorded sound pressure levels. The experimenters on the show tried a series of frequencies as low as 5 Hz, attaining a level of 120 decibel
s of sound pressure
at 9 Hz and up to 153 dB at frequencies above 20 Hz, but the rumored physiological effects did not materialize. The test subjects 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 lung
s.
Another show, Brainiac: Science Abuse
, claimed to have performed an experiment using 22.275 Hz (according to the show's producers used by Japan's police
and tested by the French military
). During the programme, 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. However, sound at this frequency at a significant volume cannot be generated by television speakers, nor by most subwoofers, nor by the cassette-tape boombox
used to generate the note for the test subject. 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.
, says that there is no reliable evidence for nausea and vomiting caused by infrasound.
Loud concert levels of subwoofer arrays have been cited as causing lung collapse in individuals who are very close to the subwoofer, especially for smokers who are particularly tall and thin.
In September 2009, London student Tom Reid died of sudden arrhythmic death syndrome (SADS) after complaining that 'loud bass notes' were 'getting to his heart'. The inquest recorded a verdict of natural causes, although some experts commented that the bass could have acted as a trigger.
Air is a very inefficient medium for transferring low frequency vibration from a transducer to the human body. Mechanical connection of the vibration source to the human body, however, provides a potentially dangerous combination. The U.S. space program, worried about the harmful effects of rocket flight on astronauts, ordered vibration tests that used cockpit seats mounted on vibration tables to transfer "brown note" and other frequencies directly to the human subjects. Very high power levels of 160 dB were achieved at frequencies of 2–3 Hz. Test frequencies ranged from 0.5 Hz to 40 Hz. Test subjects suffered motor ataxia, nausea, visual disturbance, degraded task performance and difficulties in communication. These tests are assumed by researchers to be the nucleus of the current urban myth.
Infrasound
Infrasound is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high...
frequency that would cause human
Human
Humans are the only living species in the Homo genus...
s to lose control of their bowels due to resonance
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
. There is no scientific
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...
evidence
Evidence
Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or were themselves proven via evidence, to demonstrate an assertion's truth...
to support the claim that a "brown note" (transmitted through sound waves in air) exists.
The name is metonymy
Metonymy
Metonymy is a figure of speech used in rhetoric in which a thing or concept is not called by its own name, but by the name of something intimately associated with that thing or concept...
for the color of human feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
. Frequencies supposedly involved are between 5 and 9 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
, which is below 20 Hz, the lower frequency limit of human hearing. High power sound waves below 20 Hz are felt in the body, not heard by the ear as sound. The only other vibrations titled with colors are the colors of noise
Colors of noise
While noise is by definition derived from a random signal, it can have different characteristic statistical properties corresponding to different mappings from a source of randomness to the concrete noise. Spectral density is such a property, which can be used to distinguish different types of noise...
and blue note
Blue note
In jazz and blues, a blue note is a note sung or played at a slightly lower pitch than that of the major scale for expressive purposes. Typically the alteration is a semitone or less, but this varies among performers and genres. Country blues, in particular, features wide variations from the...
s.
Television show tests
MythBustersMythBusters
MythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...
used twelve Meyer Sound 700-HP subwoofer
Subwoofer
A subwoofer is a woofer, or a complete loudspeaker, which is dedicated to the reproduction of low-pitched audio frequencies known as the "bass". The typical frequency range for a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below...
s—a model and quantity that has been employed for major rock concerts. Normal operating frequency range of the selected subwoofer model was 28 Hz to 150 Hz but the 12 enclosures at MythBusters had been specially modified for deeper bass extension. Roger Schwenke and John Meyer directed the Meyer Sound team in devising a special test rig that would produce very high sound levels at infrasonic frequencies. The subwoofers' tuning ports
Bass reflex
A Bass reflex system is a type of loudspeaker enclosure that uses the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical closed box loudspeaker or an infinite baffle mounting.A reflex port is the distinctive feature of a...
were blocked and their input cards were altered. The modified cabinets were positioned in an open ring configuration: four stacks of three subwoofers each. Test signals were generated by a SIM 3 audio analyzer, with software modified to produce infrasonic tones. A Brüel & Kjær
Brüel & Kjær
Brüel & Kjær is a subsidiary of UK-based Spectris plc. Brüel & Kjær is a manufacturer and supplier of sound and vibration measurement apparatus. The company headquarters is based in Nærum, Denmark...
sound level analyzer, fed with an attenuated signal from a model 4189 measurement microphone, displayed and recorded sound pressure levels. The experimenters on the show tried a series of frequencies as low as 5 Hz, attaining a level of 120 decibel
Decibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
s of sound pressure
Sound pressure
Sound pressure or acoustic pressure is the local pressure deviation from the ambient atmospheric pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water...
at 9 Hz and up to 153 dB at frequencies above 20 Hz, but the rumored physiological effects did not materialize. The test subjects 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 lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s.
Another show, Brainiac: Science Abuse
Brainiac: Science Abuse
Brainiac: Science Abuse is a British entertainment TV show with a science motif. Numerous experiments are carried out in each show, often to verify whether common conceptions are true or simply to create impressive explosions...
, claimed to have performed an experiment using 22.275 Hz (according to the show's producers used by Japan's police
Police system of Japan
Law enforcement in Japan is provided by the Prefectural Police under the oversight of the National Police Agency or NPA. The NPA is headed by the National Public Safety Commission thus ensuring that Japan's police are an apolitical body and free of direct central government executive control...
and tested by the French military
Military of France
The French Armed Forces encompass the French Army, the French Navy, the French Air Force and the National Gendarmerie. The President of the Republic heads the armed forces, with the title "chef des armées" . The President is the supreme authority for military matters and is the sole official who...
). During the programme, 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. However, sound at this frequency at a significant volume cannot be generated by television speakers, nor by most subwoofers, nor by the cassette-tape boombox
Boombox
Boombox is a colloquial expression for a portable cassette or CD player. Other terms known are ghetto blaster, jambox, or radio-cassette. It is a device capable of receiving radio stations and playing recorded music , usually at relatively high volume...
used to generate the note for the test subject. 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.
Physiological effects of low frequency vibration
Jürgen Altmann of the Dortmund University of Technology, an expert on sonic weaponsSonic weaponry
Sonic and ultrasonic weapons are weapons of various types that use sound to injure, incapacitate, or kill an opponent. Some sonic weapons are currently in limited use or in research and development by military and police forces. Others exist only in the realm of science fiction...
, says that there is no reliable evidence for nausea and vomiting caused by infrasound.
Loud concert levels of subwoofer arrays have been cited as causing lung collapse in individuals who are very close to the subwoofer, especially for smokers who are particularly tall and thin.
In September 2009, London student Tom Reid died of sudden arrhythmic death syndrome (SADS) after complaining that 'loud bass notes' were 'getting to his heart'. The inquest recorded a verdict of natural causes, although some experts commented that the bass could have acted as a trigger.
Air is a very inefficient medium for transferring low frequency vibration from a transducer to the human body. Mechanical connection of the vibration source to the human body, however, provides a potentially dangerous combination. The U.S. space program, worried about the harmful effects of rocket flight on astronauts, ordered vibration tests that used cockpit seats mounted on vibration tables to transfer "brown note" and other frequencies directly to the human subjects. Very high power levels of 160 dB were achieved at frequencies of 2–3 Hz. Test frequencies ranged from 0.5 Hz to 40 Hz. Test subjects suffered motor ataxia, nausea, visual disturbance, degraded task performance and difficulties in communication. These tests are assumed by researchers to be the nucleus of the current urban myth.
See also
- Acoustic resonanceAcoustic resonanceAcoustic resonance is the tendency of an acoustic system to absorb more energy when it is forced or driven at a frequency that matches one of its own natural frequencies of vibration than it does at other frequencies....
- Brown noise
- "World Wide Recorder ConcertWorld Wide Recorder Concert"World Wide Recorder Concert" is the 17th and final episode of season 3 in the Comedy Central series South Park. It was originally broadcast on January 12, 2000.-Plot synopsis:...
", a South ParkSouth ParkSouth Park is an American animated television series created by Trey Parker and Matt Stone for the Comedy Central television network. Intended for mature audiences, the show has become famous for its crude language, surreal, satirical, and dark humor that lampoons a wide range of topics...
episode