The Problem:

My door speaker (and only that speaker) is crackling/has loud static overtop of the music. The speaker is not blown (i took apart the door and the speaker itself was fine) and still plays music but with just louder static overtop. However this only occurs when i turn up the head unit volume above 5 ( max is 30). Also my sub woofers and amp are no longer working. How this happened is provided below.

My car is a 91 nissan 240sx with a pioneer mosfet 50Wx4 head unit, and 4 aftermarket 4x6 100 watt Pioneer speakers. I also have two 12in Rockford punch1 sub woofers with a 900 watt Rockford punch amp (model 301s). This audio set up was professionally installed and has been working well for about 7 years with absolutely no problems even while listening at max volume.

What happened:

Lately i had not been listening to the system that loudly for some time. About 2 weeks ago i turned on my car and turned up the volume on my head unit(not far below max)shortly thereafter. A few seconds later all sound from all 4 of my speakers and the bass from my subs completely shut off and stopped. The head unit was still on and volume still the same but absolutely no sound. I then turned down the volume and turned the head unit off and on and the music was back but there was static coming from just my door speaker overtop the music. I didnt check to see if my amp and subs were still working. I cant really remember but im pretty sure i did not smell any burning at all. Anyways thinking that my door speaker was blown I ordered 2 new 250 watt 4x6 speakers. Yesterday i took the drivers side door apart and installed one of the new speakers. All of the wires were secure and the circuit board looked fine and nothing was wrong with the old speaker. However i still had the same problem with the static. So i ended up installing the new speaker in the passenger door and left no speaker in the drivers side. I took apart my amp n everything was fine but it wont power up.Plz help whats wrong