In Taos, Researchers Can Hum It, but They Can’t Name That Sound

People move here for the peace and quiet.

Drawn by cool, dry mountain air and intoxicating vistas, they hope for a refuge from the hassles of modern life.

But for some residents of this town of 4,000, the idyll has been shattered.

For more than two years they have been hearing a continuous, irritating sound that usually is compared to the throb of a diesel engine or a tractor. No one knows the cause, and while most Taos residents don’t hear it, those who do complain that it shatters their concentration and disturbs their sleep.

Last week, a scientific team reported that a battery of tests had found no unusual sounds, seismic vibrations or electromagnetic signals in the area.

But the researchers are not giving up. They say the mystery has piqued their interest, especially as they learn of people throughout the United States and abroad who report hearing a similar sound.

“There are all sorts of possibilities,” said team leader Joe Mullins, a University of New Mexico mechanical engineering professor. “We may be seeing some unusually sensitive ears combined with a background of electrical noise or acoustical noise.”

Added Joe Kelly, an ear-nose-throat researcher at the university’s medical center: “I believe this is a real phenomenon. I do not believe this is psychological.”

With the obvious external causes ruled out for the time being, Kelly said the team will focus on the hearers themselves.

The “sound” may not even be a sound, at least not as it is usually experienced, said Kelly, who suspects a link to the phenomenon of oto-acoustic emissions--low-frequency noises produced by the ear.

While the debate continues, some residents afflicted by what the media has dubbed “the Taos hum” are planning to leave.

Bob and Catanya Saltzman are selling their custom-designed mountainside retreat and moving out of the country.

Catanya Saltzman was the first person in town to go public with her experience in a March 19, 1992, letter to the Taos News. Soon others were calling to report that they, too, could hear the sound.

Bob Saltzman, who began hearing it a few months after his wife, says the couple has grown frustrated with what they consider to be governmental indifference.

While many causes have been proposed, none has panned out.

Some people wondered if a military project was causing the sound. Special radars or extremely low frequency radio waves used to communicate with submarines might be at fault, they reasoned.

The local waste water treatment plant and a diesel generator at the new golf course were briefly suspects, but these were ruled out by an acoustical engineer.

Answering a chorus of complaints from constituents, Rep. Bill Richardson (D-N.M.), who sits on the House Intelligence Committee, asked staffers to investigate.

Richardson spokesman Stu Nagurka said that while the inquiry continues, it has not come up with anything solid.

Richardson and Rep. Steven H. Schiff (R-N.M.) also sought to form an interdisciplinary team of scientists from Los Alamos and Sandia national laboratories, the Air Force’s Phillips Laboratory and the University of New Mexico to study the problem.

But a field study of electromagnetic, acoustical and seismic energy turned up little that was unusual, Mullins said.

Geophones--used to measure vibrations in the earth--picked up the sounds of a gopher tunneling but no seismic activity.

Magnetometers detected lightning and energy from the Taos power grid, and while some abnormalities were noted, none explained the sound, Mullins said.

Kelly said that when researchers asked hearers to duplicate the sound using signal generators, they selected low-range frequencies from 33 to 80 hertz, similar to those recorded in Britain, where thousands of people known as “hummers” have reported hearing the sound since the 1970s.

And Kelly has ruled out a hearing disorder known as tinnitus. “These people might have some special spectral sensitivity,” he said. “Another possibility is that they’re emitting sounds that they can hear.”

Such low-frequency oto-acoustic emissions occur when the stiff hair cells in the fluid-filled inner ear move, causing the eardrum to act as a speaker. Research shows that hair cells can “tune” themselves to hear a particular frequency, Kelly said.

The next phase of research will require the construction of new instruments to measure low-frequency sound in the ear.