GREEN BAY, Wis. (AP) -- Bob and Leona Ehrfurth still don't know what's causing the rumbling noise and vibration plaguing the Green Bay home where they've lived for 42 years.

But their problem is getting plenty of attention after the story hit it big on the Internet.

Bob Ehrfurth says he's gotten calls from the United Kingdom and from Maine, California and Portland, Oregon, among other places.

His wife compares the noise to an idling semitrailer truck outside the door -- only there's nothing there.

The Ehrfurths say it started two years ago, soon after St. Bernard's Parish across the street had the roofing, chimney and ductwork on a wing of its school redone. They now suspect the ducts could pick up sounds from industries and reflect them at their house, although the problem is intermittent, making it harder to diagnose.

Alderman Andy Nicholson says he's experienced the noise and hopes to bring various parties together soon to work on finding a solution.