I know the title is a bit confusing, but here it is. I have been noticing that my Cab sounds a bit off, by the time the jam / practice is over. I am playing out of 4x10 GK neo + MB800 head. The cab is sitting on its side on top of another cab (inactive), the room we jam in is pretty small, so everything is close together. When we start playing everything sounds very nice, the sound is deep and punchy on the low strings, high end is very determined. Maybe its just my ears getting tired, but roughly one hour in the practice - sound becomes ... for the lack of better word ..to metallic / screechy / almost farty, esp on the low notes. Wonder if this is something to do with the Cab. I will try to change my pick up battery though it could be that. Any one else having similar experiences ?