sub hz or freq control

hello guys this is my first post. i want to ask you guys what is a good brand to control my subs hertz. my setup is

alpine 7995

ppi 2350

mb quart rce216

mb quart dtc 6x9

ppi 4100

two JL 13w6v2.

i need to make the sub hit lower(deeper)

wat the heck are ppi'z?

I would start by stuffing your sub box with poly fill to slow the sound waves down.  It makes the subs sound lower.

Next i would check your x-overs.  I personally would set a 13" sub to 65-70hz and down, since it can't play the higher bass to whell.   This will inturn make the amp only worry about amplifying the lower stuff, , the stuff you want.

You got the 6x9's i see, so you can try and give them 65hz and up, and you should have a slightly better low output.

65hz and up for the front and rear speakers will probably lead to smelly speaker syndrome (sss) due to the limited amount of heat that the small voice coils in these speakers can dissipate. I would set the crossovers higher for sure. Disconnect the subs entirely. Next set the gains on the amp properly. To do this is simple. Turn the bass and treble to zero (no extra / no less) and if the cd has an eq, set it to flat. Turn the gains on the amp all the way down. Unplug the rear rca cables from the 4 channel amp. Turn the cd player volume up to about 80% (assume 80% as being 100%), turn the gain up on the amp until distortion may be heard, adjust the crossover up or down to see how the speakers play frequencies at this level and you'll understand why it needs to be higher. Unplug the front rca's, plug the rear back in and do the same. Plug in both rca's and adjust the rear gain, probably turning it down so as the rear speakers do not overpower the front. Disconnect all rca's from the 4 channel amp. Set the gains in the sub amp (with the sub level control at about 70% and the main volume at 80%) and again play with the crossover, you will find a good balance on the crossover by listening to it, too low and you miss out on some necessary and playable midbass. Too high and the midbass is overwhelming and distorted. Plug in the 4 channel amp again and have a listen.

Your cd player does not have no clipping preouts, this means that the cd player can actually distort the signal before it is even amplified, thus 80% on your volume control should be viewed as 100%, on some songs you may be able to play a little higher. When you are setting your gains play the same song over and over and over.

Ignore the polyfill for now, get yours gains and crossovers set first.