Under performing System

[zjKrawler]

I have 2 SKAR EVL 12D4S in a ported box I  think net is 2.99 cu ft. per chamber. port length is around 18' I believe. I also have it wired in parallel from a pair of SKAR RP 2000.1D's going to each sub. That should be 1400 WATTs at 2 Ohms which its wired to. it sounds great except my SPL is way under par for equivalent set ups. 116.4 Db. right around 45-50 Hz I'm using 1/0 gauge power and ground running 18", 12 gauge dual line for speakers. I have a D34 Optima yellow top at 750 CCA I'm not getting much of a voltage drop and no change in idle/ 2000rpm and although short lived no change with vehicle off. Head unit is -2 bass, loud off, gain matched @50ish % on both amps set to same base knob,  0db boost, subsonic off and low pass around the 75% range which I think would be 200hz. I have ran gain full and bass knob up at +2 bass on head unit but got a smell from subs not bad but pungent glue smell, came off that volume quick mainly from smell and worried about back hatch. this is all in the back of a 96 Jeep ZJ gran Cherokee. I do have new Alt at 250 amps and second battery in the works. 1. I've been eyeing the Rockville Destroyer 12d2 and grabbing a set of these if I'm stuck with needing a new box or if I'm greatly over powering my subs. 1250 RMS at sub 1400 RMS at amps. from what I've seen that's not even a constant as it changes through out the song and note being played. If the combo I have is fine and a new box is needed can someone help with some dimensions please.. mainly adding the port. this is the first ported box I've ever done. box is dual outside ports facing front at 1.75'' W x 15' H inside port's (box volume including wall thk) 36.5" W x 17.5" H x base 20" D top 17.5" D using 0.14 cu ft for displacement of sub and 26' sq in port. 

[liteblue]

3 cubes per chamber, thats a big ass box!! Or 3 cubes total?

 

I would try tuning again. Are you using a dmm, oscope or dd 1, cc 1? Those potentiometers are so sensitive, strongly recommended using a meter so you have some idea of how drastically settings are being effected. Even if its not the fancy SMD Damore toys. I recently fine tuned my set up and it got louder and gained some clarity. Same box same sub, sounds way different.

 

You can even find people on Facebook marketplace or Craigslist offering to use their dd1 and cc1 to tune your set up for a fee. Local car audio shop might do it for a few bucks aswell. 

 

Why -2 bass at the head unit? Flatten that out or use - if it's too loud.

 

Try setting gains  -10 db or even -15 db overlap and use some bass boost. Bass boost is ookay if you use wisely. The DD 1 manual even suggests it. 

 

200 hz sounds a little high. I would back that down to the 120 ish range. Crossovers are not a flat wall, it is a roll off point. Is the box ported? THEN USE the subsonic!!! Check if your amplifer is 12 or 24 db roll off and adjust accordingly.

 

The amifer is attempting to reproduce 10 to 200+ hz during a song instead of 30 to 120. I assume your box has an f3 higher than 10 and rolls off before 200 hz. At full power, full volume, those notes will be quieter do to the mechanics of the enclosure. And they are robbing power from notes that ARE in the enclosures bandwidth. My experience is  a large box with low tuning means Low bandwidth. But this is not always the case. 

 

How old is the yellow top?