I'm not sure if this is the place to put this, but I need some help troubleshooting a problem that popped up tonight at practice that has left me puzzled. I have a GK neo 212 cab that had the bottom speaker start making a crackling sound when I pushed the E string a little tonight. Not quite a distortion, more of a high crunch but only when I dug in. If I turned the amp up a little is seemed to get worse with volume. I checked and it's only in the bottom speaker not the top one, which rules out connections, cables, processing, and the amp in my mind. I figure it's maybe a bad connection or the speaker is cooked (I replaced the top speaker earlier this year, it was farting and was blown) Then all of a sudden, it started working perfectly normal. I could push it to stage volume (which still isn't that loud) and not a single issue with it for the next hour we practice. I gigged the amp with another cab three shows this weekend and not a single issue. So I'm really not thinking it's the amp. The 212 cab I normally use for practice, and I'm an adult whom has played professionally, and I don't abuse my gear. I run my tone mid heavy and roll the lows out. The bass I was using was a passive p bass. Any ideas? I guess I was thinking that if a speaker is blown it's blown and doesn't intermittently make noises like I experienced tonight. I'm just confused right now. As I said I've replaced the top speaker in the cab, and tonight it was working perfectly. I'm going to leave this up to your thoughts. I'm at a loss right now. It's a nice sounding cab and is perfect for smaller shows and I always have foh support, so it's never pushed very hard. I'd like to use it for a few shows coming up but I don't trust it right now. Any ideas or help would be greatly appreciated.