well a quick google tells me that I have forgotten a lot more than I know, and didn't even hear right to begin with... anyway, here's a great link (which perhaps you've already found....):
Wolf Tones
sounds like a particular area of resonance in an instrument (strings especially) that causes the note to sound differently than other notes.

I've had fun trying to find the resonant notes in stairwells and other closed, resonant spaces. this is a similar phenomenon, I guess.

formerly known as etaoin...