I have a Carvin R600 head and some sort of cab with an 18" black widow speaker in it that I play through, and last week it was working perfectly, nice and loud, no clipping or distortion, but today at band practice I plugged in and there was this inconsistent low-volume distortion. The first thing I assumed was that it was my bass's battery, because it had a very similar sound to the battery being dead. Put two different ones in, and nothing. I tried another bass in the amp and had the same problem, so it wasn't that. Tried a new cord, same thing, tried a new speaker cable too, and the exact same thing. My Peavey TNT115 worked fine with everything. The speaker's not visible and my guitarist said the speaker was intact, not torn to shreds or anything of the sort- besides, when I've seen that happen it's the high end that's more audible than the low end, such is the opposite in this case. The distortion is mostly on high strings. I play a 6 string, and on the G and C strings, it's barely audible, and on lower strings, it gets less distorted and is more loud and bassy, but it's still there. My question is, where could the problem be? Keep in mind a week ago it was working perfectly, no problems, but I turn the amp on a week later and the first note I play is a small fart. How is this possible, to revisit it and it's suddenly ****ed?