I have a 1974 810, with 6 speakers that are completely original and 2 recones. As of late, it's been crackling and I can see light through one of the speaker surrounds. It's only one speaker that I'm noticing it from. This cab doesn't have a horn, and the only other post I've found that references this phenomenon with an 810 didn't have a clear diagnosis, so I apologize in advance if this is a repost, or I missed something else in my search. I tried to get video of it this morning, but it's either too dark, too bright, or my camera is too crappy to capture exactly what's going on, but I'm able to reproduce it with different speaker cables, a 1976 SVT head, an Ashdown ABM 500 EVO-II, and a GK 1001-RBII, with three different basses and three different instrument cables, all going directly into the input on each amp. At this point, I'm pretty certain it's the cab itself. I haven't had a chance to pull the speaker - that's my next step, but I figured I'd see if anyone else had any ideas in the meantime. I know at least one other speaker needs to have the dust cap re-glued, but I would assume that wouldn't really cause anything like this to happen? Help?