Issues with a speaker and amp, Help please.... Options

[dabazied]

Ok. I finally got around to wiring up an aftermarket preamp. Its a 100x4. Ive never changed the speakers in my car since I got it, just thought id throw that in there. I know I need to change all 4, thats not my issue(i dont think atm). Ok, I have the amp hooked up to the two back speakers. The passenger rear speaker is working fine(sounds a bit crappy at times, but I know they need to be replaced anyways). The drivers rear speaker went a little crazy on me. It played for a bit(5mins) and then a song with too much bass came on and there was a crackle. I turned em down immediately. The other speakers still play fine. The driver rear didnt come back on after that, no rattle, no quiet playing nothing. Then there was a couple times where the speaker came back on for a few seconds each time. I plugged it back into the headunit instead of the amp to try that, and it still didnt work. My question is, is this a blown speaker, or more likely a loose connection wire/faulty wire? Usually when ive seen blown speakers theres a hum, crack, or somethin, never heard complete silence before, thats why I ask.(when I ran the wires from the amp, I wen