OT: I can relate, the other night, about every 5 seconds my wife and I kept hearing a strange vibration sound. It appeared to be coming from the kitchen area. But when we walked around the kitchen, the sound kept moving in the opposite direction we walked. I thought maybe it was the sump pump (for those who know what those are), so I went downstairs, no go, from the basement the sound appeared to be above me in the kitchen. Back to the kitchen, and I would walk towards the sound then it would be behind me again, I would walk to the left, and it would eventually be behind me again. So taking Alan's advice on how to position a Sub, I got on all fours, luckily the wife didn't have a camera, and crawled around the floor, as the sound approached me, I looked up, I felt so foolish, it was our 4 month old's little bouncy seat, that has a built in vibration to get your kid to sleep.
We laughed for an hour, we hadn't had a good laugh like that in years...
Anyway, Bray has a good idea, could it be something totally differant then the sub? Possibly a picture nearby, or a heating vent on the floor.
Has anything changed in your environment since it DIDN't make this noise?
