I have a Larrivee acoustic with an under-saddle piezo. A while back it started making a horrible shrill buzzing noise. I don't hear it when playing acoustically. I can't duplicate it when playing into an audio interface and recording it. In the latter case I get a little buzz but not the horrific shrill thing that comes out of the PA. I though maybe since I couldn't duplicate it at home that it was a function of seasonal-related buzzing that had gone away but I played another show last night and it was back. The guitar has a bit of a raised tongue and I think that's where the buzzing is coming from. I've heard this sound before, from a cheap guitar with radio shack piezos under the bridge. I was experimenting with using it for acoustic sounds. It had a low spot on the zero fret at the G string and when the G was played open it would buzz against the first fret. On that one note only, I would get the same horrible shrill ringing buzz. Didn't sound so bad acoustically or through mag pickups, just through the piezo. Has anyone else experienced this? Is this a known property of piezos -- to emphasize the sound of metal strings buzzing against metal frets?