To Paul Porcaro, it sounds like the idling engine of a faraway car. His wife, Sadie, hears moving water.

However it is described, "The Sound" can't be found.

For the past two years, the Porcaros have been troubled by a strange and unexplained noise at their home on Anderson's east side.

"We keep the radio on during the day just to drown it out," Paul said. "At night, it's hard to sleep."

©John P. Cleary/The Herald Bulletin
Paul and Sadie Porcaro in their home.

It is worth noting that Paul and Sadie are not crazy and that the couple have investigated every plausible explanation. "The Sound" is certainly not the hum of a refrigerator, the buzz of fluorescent lighting or the drone of a neighbor's television set.

In fact, "The Sound" is a relatively new phenomenon. The Porcaros moved into the house on Lansdown Way in December 1988. Everything was fine for 17 years, until "The Sound" appeared and never went away.

"I was concerned that something was wrong," said Joseph Porcaro, Paul and Sadie's son, who relocated his parents from New York when he accepted a job at Community Hospital. "I called several professionals."

The Porcaros called Sweigart's Plumbing to have the pipes inspected and the sump pump replaced, but it didn't help. They called an electrician to check the wiring, a building inspector and even Mustin Builders, which erected the home in 1973, but "The Sound" persisted. They had the air conditioning and furnace inspected. They even called Anderson City Utilities, which provides the home with water, sewer and electrical services. "The Sound" would not die.

Paul said everyone who listened heard the sound, but none could find the source or offer an explanation.

Set foot outside the Porcaro's home, and "The Sound" disappears. But at night, the couple says, it grows louder.

Paul wears hearing aids in both ears, but he's convinced that has nothing to do with it.

"When I take out the hearing aids, it gets even louder," Porcaro said. "It's a vibration."

"The Sound" bears more than a passing resemblance to the "Kokomo Hum." First reported in 1999, it was heard by dozens of residents of the town and, many believe, caused them to fall ill with fatigue, nosebleeds, headaches and diarrhea. More than 80 complaints were submitted to the office of Sen. Richard Lugar and the curiosity received media attention from ABC News and others.

Things got so bad the town hired a consultant, Jim Cowan of Massachusetts-based Acentech, to undertake a 10-month study of the sound. He traced the hum to low-frequency and infrasonic tones generated by industrial sources, namely a cooling tower fan on the roof of Kokomo's DaimlerChrysler Casting Plant and an air compressor fan at Haynes International.

"This phenomenon is not isolated to Kokomo, Indiana, USA," Cowans told the Kokomo Tribune. "I have been contacted by people across the country, as well as from other countries around the world, who are having similar experiences to those in your community. To adequately solve this problem, any further study into this phenomenon should therefore be on a national, if not international, level."

"Hums" have been reported in Taos, New Mexico, Auckland, New Zealand and the United Kingdom. A Web site pertaining to the "Taos Hum" has been created and lengthy entry about "The Hum" is available through Wikipedia.

I visited the Porcaros to hear "The Sound" for myself. Paul hears the sound throughout the entire house, but Joseph said it is strongest in the bedroom near a west-facing window. I stood, strained my ears and distinctly heard it.

The sound I heard was very distant; if it were a car running, it would have to be blocks away. In fact, I didn't so much hear it as feel it. It had a hollow quality, like air passing through a length of pipe. Once I knew what to listen for, I heard the sound all over the house, too.

"It doesn't bother you after a while," said Sadie, 86.

Joseph pointed out that "The Sound" is constant, but it changes at irregular intervals.

"It modulates a little bit," Joseph said. "It's not constant. It changes frequency."

There is little commercial activity near the Porcaro home and no industrial operations. But power lines have been known to emit a humming sound, and there is a substation behind East Side Middle School, just a few hundred yards away. Power lines run behind the Porcaro home, between Lansdown and Roby. There appears to be a utility easement just 50 yards or so north of the Porcaro home.

But the Porcaros have not considered moving.

"We love the area; we love the house," Paul said. "But this is terrible. It's like we have a haunted house."

But Joseph has wondered whether, when the day comes, he must inform the buyer or real estate agent about "The Sound."

"Maybe it's part of those disclosure agreements, I don't know," he said. "Whoever buys it will be buying a mystery. They should pay more for that."

"Hums," low-frequency sound phenomena similar to the one experienced by Paul and Sadie Porcaro, have been reported in Taos, N.M., the United Kingdom and New Zealand. In the case of the "Kokomo Hum," the sound was traced to local industry. But here are some more interesting explanations that have been suggested:
  • Man-made noise: Low-frequency sounds generated by industry or stereo subwoofers can be amplified by walls and structural geometry
  • Infrasound: Geological changes and plate tectonics can generate sounds too low to be perceived by the human ear, called infrasound
  • Pulsed microwaves: Similar to the microwave auditory effect, in which audible clicks are produced by microwave frequencies generated inside the human head
  • Extremely low-frequency communication systems: Submarines communicate using ELF radio transmissions that may produce other audio effects
  • Ionospheric heaters: Antennae in Alaska, Puerto Rico, Norway and Russia used to heat the ionosphere create light effects similar to the aurora borealis and may create sound, as well
  • Tinnitus: A hearing condition that produces ringing or "whooshing" in the ear when no actual sound is present
  • Tensor tympani: According to a German study, vibration of the tensor tympani, a muscle that tightens the eardrum, may cause a humming effect
- Source: Wikipedia