I have a Gallien-Krueger MB212 that sounds a little weird lately. About a month ago I've noticed that of and on, I'll sound a little distorted, lacking low end and sustain. Sometimes it would come back to normal and I assumed it was something to do with the wiring of whichever building I was in. Luckily it was never like that for any gigs. Lately, however, it's only been distorted, and sounded kind of normal whenever there was slapping or popping going on, or just harder playing in general. So I've concluded, after testing two basses, three cables, multiple outlets and removal of all pedals from the chain, that it's the speaker(s). Should I take it in to repair? It's still under warranty. Does anyone have any clue what they'll do or charge? Or should I replace them myself, and if so what kind of speakers should I get? It's 500w. Thanks for your input.