SOME NOTES William Beaty 1997 If the "Hum" is tinnitus (and arises in the brains of affected individuals), then why do these individuals note the disappearance of the hum when travelling to some (but not all) other states, or to other countries, only to find that it immediately reappears when they return? If the "Hum" is caused by microwave beams, why does a faraday cage have no effect on the perceived intensity? If the "Hum" is acoustic, and hum-sensitive individuals simply have an extended low-freq hearing cutoff, then why do microphone measurements show no spectrum peaks? (note: A.H. does find spectrum peaks in Denmark hum. But U. of NM finds none in the Taos NM area.) If the "Hum" is acoustic, why do some hum-sensitive individuals turn out *not* to have extended low-freq hearing sensitivity? There is one report of a hearing-disabled person who suffers from the Hum. If the hum is acoustic, then a thick-walled chamber, such as a pressure chamber, should shield it. No reports of this having been tried. If the "Hum" is from local industrial sources, why does it continue even during long term, wide-area power blackouts? If the "Hum" is from tornadoes, weather, aircraft, street sweepers, etc., why does it usually continue unceasingly for years? Sources of transient hums cannot be used to explain a continuing hum. If the "Hum" has a geologic source, what is the mechanism which converts underground stresses or movements into a continuous signal around 60hz - 80hz? And why don't microphones pick it up? If the "Hum" is caused by human electromagnetic perception of ELF waves, then hum-sensitive individuals should also be able to hear the magnetic field around a 60Hz-powered coil. They should perceive power transformers as being loud hum sources, or if the perception is nonlinear, then the more powerful field should swamp out the normal "Hum" they hear. If the "Hum" is caused by human electromagnetic perception, then why did the U. of NM people find no anomalous signals between 10Hz and 1000MHz? (Note: at VLF frequencies the E and the M components might be separate. A coil-based antenna might not detect electrostatic vibration, and a capacitor-based antenna might not detect magnetic vibration.) If the Hum is low frequency electromagnetism, then it should be easy to prove: build a simple hum-transmitter, such as a signal generator, a power amplifier, and a coil. Encapsulate the coil to limit audio vibration but pass magnetism. If hum-sensitive people can hear the signal from the coil, but non-hearers cannot, then this would be strong indirect evidence for an EM source. Hum-hearers report that ear plugs work temporarily, but soon the Hum is heard again even with plugs. One person reports that use of just one earplug can give some relief. The hum commonly causes marital strife, since usually only one partner can hear it and the other cannot. Women report problems with the hum more often than men. The hum is perceived as louder indoors than outside. The hum seems louder a few feet from a wall, but seems less loud at the wall's surface. If the hum is electromagnetic, then a magnetic shield room with thick iron walls should shield it. No reports of this having been tried. If EM, then a negative feedback coil system might cancel the signal and thereby act as a shield. Micheal Theroux hum article in Borderlands magazine. Detector: suction-cup telephone pickup coil with NIB magnets on either side, placed in the center of a long piece of plastic sewer pipe. ***************************************************************** Some info from John Daws about the "Bristol Hum" in the UK Sounds like an idling diesel engine. Most "hummers" are over the age of 50 At least one partially deaf person hears the hum without using a hearing aid Radar signals can be ruled out, since aluminum foil enclosures do not attenuate the Hum. If a signal generator and loudspeaker is used, a zero beat can be heard around 100Hz Steel enclosures slightly attenuate the perceived hum, but only if greater than 1/8" wall thickness. J. Hall of Bristol UK committed suicide in 10/96 after having been driven crazy by the hum. The Hum is perceived as loudest when the modulation frequency is 2.5 - 3.5Hz.