My car came with the stock Monsoon sound system and it always sounded great. Some years back, I installed an Alpine head unit. Got sick of always fumbling with all the buttons, so I threw my stock Monsoon back in today. Well, the back speakers are crackling and popping like crazy...like the bass is all the way up, but it's only on -3.

Popped my head under the rear deck 6x9's, and for SOME reason, I cut the black/red wires that connect the two sides and they're just "dangling" there. I have no idea when or why I did this. Think it'd explain the crappy sound coming out of them?

That could explain some of the issue, I know my buddy installed new speakers in his Grand Am with the monsoon and we had issues with the separate highs and lows... I'd say re connect those and see whats going on, could be that, or a short or loose connection somewhere, trace back any wires that you messed with in the system, you might find an answer.

^ y0 hommie, you must be trippin' y0, that ain't gonna do it bra

of course, if you're only feeding + to the speaker you got a broken circuit and they won't sound good.
just reconnect the loose wire back up and you'll be good.

Fixed those wires last night and it sounds better, but I really do think one of the speakers is blown. Ugh...