Drawing big power with only 13volts

Howdy Folks. Newb here. I was having some problems and wanted some input.

Starting out with what I have.

US Acoustic 125 x 4
running polk components in front and 6x9s rear
Us Acoustic D-1000
pushing mtx 9500 15 @ 2ohms



I've got a car that the charging system runs at 13 volts and is pcm regulated so i cant control it. I've had problems with my door and deck speakers laying down and just not sounding good. I did the major 3 using 4 gauge and those speakers sound alot better. Now my sub is still not hitting hard. I've used this to amp to kill 3 jl w6's before at 1 ohm. The new sub im trying to run at 2 ohms. Im trying to figure out if the sub isnt hitting hard because the amp isnt strong enough or because the voltage is dropping to low. I hear alot of people say no to cap's but no one can tell me why they're so bad.
Thanks for any input

 

thanks man...I've got a bud with a camera i'll try to get some up. It was a premade internet box. Suppose to be 2cuft. which does seem a little small. i dont know if i could put a bigger box in it unless i build it inside of it.

 

I've got the same head unit , pedro. I really like it

 

i've built one before that sounded pretty good but it was just a "this looks like a good size" type a deal. I dont know the specifics of how build one to get the best sound out of it. I tend to listen to alot rock and i dont know how important that is in building a box. Some people say sealed is the only way to get that nice crisp beat.

But you guys believe my box is just too small then?

 

could a Autotek SS1900.1D kick the snot out of this at 2ohms?

 

yep 13.0 volts. regulated by the pcm...Thats what i believe to be the problem...Drove around alot today and my door speakers started to lay down again...Im thinking its almost undeniably a voltage problem. The question is how to fix it?

 

Dodge SRT4... The speakers start getting distorted and become quieter. All of these cars run the same voltage so it isnt just my car.

 

Im running a crossover. Does it with and without it. The gain is up maybe a quarter of the way so i couldnt imagine sending them too much power.

 

back before i rewired the alt. They would lay down with the gain bottomed out at zero.

 

I've got a seperate crossover inbetween the amp and the head unit..running it at about 50..i've got the high passes set to pass and a small amount of adj in the eq on the headunit... I just built a new box and it hits harder but not what it should. I used one of those calculators that was posted on here. It said it was tuned to 30hz. I just put the demensions i knew would fit in the car. I dont know. I have way to much $$ in this thing to sound like crap.