Re: question about blowing subs
Any speaker can be damaged mechanically or electrically and sound funky but still work. If you press the cone in evenly with your fingers you can feel if there's anything binding, that'll tell you if you have mechanical damage. Also inspect for tears in the fabric parts. A speaker doesn't have to be totally dead to be "blown".
Also look for rattles in the box or trunk before blaming the sub.
1999 Buick Park Ave Ultra
Head Unit: JVC KWHDR720
EQ: Audiocontrol EQL
Front Stage: Hybrid Audio Technologies Imagine 5.25 mids, Morel Maximo tweets
Sub Stage: Boston G3 10", 0.5 cu ft sealed
Amp: PPI Phantom 900.4
Rear Fill: Boston SE953 6X9's