Aww Tom! <b>sends hugs</b><br><br>I've noticed something similar to this. Housemate, husband and I went to a Phil Beer concert in Winchester last year. The dude's an absolute master of the guitar and he's part of the folk group Show Of Hands whom we all like. Most of the rest of the audience however were old people and whenever he plugged this black acoustic guitar in a high-pitched feedback noise was constantly sounding and us three were the only ones who could hear it! Luckily at the interval we told the sound booth and although they couldn't hear it either they fixed it :)