Does the room happen to have smooth & solid(concrete, glass,...) surfaces on the floor, ceiling and walls? It sounds to me like the room in which you're practising might just be an acoustic nightmare(too many reflections). If this is actually the case, you might want to look for another place to practise.
Originally posted by Tweak
how does feedback occur?
Feedback occurs when the signal coming from the amp gets picked up by the pickups in your guitar. Normally this should only occur when you're standing directly in front of the drivers. In a room with highly reflective surfaces, more signal coming from the amp indirectly will reach your pickups, making it harder to control the feedback.
Anyway, that's just my 2 cents...
[Edited by SPL on 10-25-2003 at 08:44 PM]
