I’m not sure if anyone would interested at this point but it all worked out in the end.
I removed the panel, grill cloth, to inspect the Mylar and found that it was wrinkled in spots. Then heat gunned it to tighten them up. Once I put it all back together the sparking on bass had stopped but the distortion was still there. I switched the speaker cables and, yep you guessed it, the amp was blown in one channel. Luckily it’s a 5 channel amp. Rinse repeat on the other speaker and now they’re back in and playing amazing music.
I think this must happen a lot.