Mysterious noise plagues Wisconsin couple's home

I can't imagine how frustrating this must be:

For two years now, the Ehrfurths have been enduring an annoying, persistent noise in their home — a low, motor-like rumble accompanied by a vibration. They can't figure out what's causing it, and it's been a challenge getting others to believe them because the problem starts and stops.

They've lived in the house at 2048 Mary Queen Road for 42 years, and it's only been the last two years that it's been a problem.

"It's like there's a semi parked right outside with the engine running, but when you look out, there isn't one," said Leona Ehrfurth, 76.

Because it comes and goes, they're having trouble getting anything done about it. Testers aren't hearing anything. City officials show up to experience the problem and find nothing out of the ordinary. Not only do these poor people have to deal with this incredibly intrusive annoyance, but they've had to also endure two years of people treating them like Grandpa Simpson because of it.

"Now they KNOW we're crazy," Bob Ehrfurth, 75, grumbled after explaining how a technical expert installed vibration-monitoring equipment in their house and failed to measure anything of significance.

"Imagine putting your pillow on the hood of a running car — you can't sleep through that," Leona Ehrfurth said. "You get this pressure in your ear. Sometimes I have to get out of the house, because I can't take it anymore."

Bob Ehrfurth can sleep through it, but he doesn't like it.

"It doesn't matter if the windows are open or closed — you still hear it," he said. "It's worse in the winter."

Luckily, though, they've managed to get a few people to confirm that there is, indeed, a "there" there:

Although the two aren't in the best of health, the problem is not with them because when they leave, they don't hear the noise, Bob Ehrfurth said.

The Ehrfurths' immediate neighbors haven't complained about the noise, but the Ehrfurths have had a few people admit hearing the noise. An engineering teacher told the city's Protection & Welfare Committee he tried to help the Ehrfurths investigate the matter, and said he experienced a throbbing sensation in his ears while in the neighborhood and in their house. A resident from about a mile away made similar complaints.

"Yeah, I've experienced it," said Alderman Andy Nicholson, who has been trying to help the Ehrfurths. "It's like an engine thing, a low-frequency vibration. I think it would be an annoyance."

But the source remains a mystery.

Here's hoping they figure it out and get some peace. Any acoustical experts out there that can help these people?