power issue

Hello all i had a few questions i just bought a kenwood kac-x811d 1600watt amp and upon hooking it up i noticed that it sounds just about the same as the kac-7201 800watt amp i had previously installed. I have also had some problems with what i believe to be the amp overheating. It will overheat in the time frame of 1 song at 1/3 the volume it then turns back on a few seconds later if i turn down the volume. I have 5 gauge running from the battery to a distribution block 9 gauge to the amp. Some one told me that a bad ground can make access heat so i replaced the ground with 4 gauge and found a better spot.

When i checked the amps amp meter before the new ground was installed it was pulling 35-45 amps now it is pulling about 45-65 and last for about 2 songs before overheating. After this didnt fix the problem i did a ride along in the back seat to monitor the amp i used snoop doggs doggy style for its awsome bass hits.   While watchig the voltage meter i noticed that the amp could drop the voltage in the car to 8 volts durring big bass hits the car is a 96 taurus with power every thing.

Well the other day i was driving and the music didnt turn back on i poped the trunk thinking i would have to look for the problem. And there it was my sub with the cone extended about 3 inchs out of the spider stuck. I opened the box and a whole bunch of bad smelling dust or a smoke came out the red highlighted portions in this pic were blowin of the spider. The subs were 2 type r 12s rms 500 watts each max 1000 watts each im just trying to find out what the problem is thanks for the help in advance.

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