Guys, so far I have my 2 JL Audio 12W4's housed in the spare tire space running off a Rockford 500a off the Sony 7700. The thing is, I am not getting the lows like I used to in my other car. They kinda just cutt off. I have turned up my gain, and lowered my crossovers and still I am not getting the lows like i want. Anyone have any feedback. The Sony headunit has a feuture which allows you to set the crossover freq from the headunit, but 67 seems to be the lowest and im thinking this is the problem. Can anyone help?

 

The box for your subs may be too small to allow for any deep bass. Check what the recommended enclosure size is for those subs, and if you are looking for deep bass...go about 25% larger than that.

Also, your enclosure may be ok, but a 500a may not have enough reserve power to get 2 sealed 12s as low as you want.

jim

 

It could be a lot of things. The box size is the most obvious. Also you might be partial to the enclosure you had before. Was it ported or sealed? One woofer or 2? What was the nominal impedance on the original box? Are you using the same type of deck that you had before? If not, try running full signal to the amp and using the amps crossover instead of the head unit's and the amps. That can somtimes lead to problems.

Let us know how it turns out.

 

Thanks for the helpful response guys. Once I get my camera fixed (gulp) hopefully i can post some pics as the dude at Myer Emco (Benji in Fairfax) did a badass job. I box in somewhat small due to the fact that we tried to keep the same trunk level as stock without losing any room, while being able to keep it stealth by putting the trunk mat on. Also, i had it switched from a 2ohm load to 1ohm and this is creating more power of the back. Also, i put my gains up all the way and lowered the freq all the way on my amp. Sounds a lot better but rattles are coming from the trunk panel on the rear window. I am getting the panels "sprayed" with synamat next month to see if that helps. Otherwise, i need to change the front amp to 1ohm as well to balance out the back and hopefully get more power. I am talking to the installer about possibly switching up the system to the strut bar which might create a bigger box, less rattling and better lows.

 

"Changing" to 1 ohm is probably a very bad idea. Most amplifiers cannot take that amount of current draw and will overheat and die. Check out the size (internal volume) of your box vs. the size recommended by JL; like the previous posters said, a small box cuts down the ability of your subs to make really low bass. Another possibility: see if your amp has an infrasonic filter on it. If that's set too high, it will cut out the lows. Turning your gains up all the way is also a bad idea. That lowers the headroom of your amp and makes it easier to drive it into clipping, which will kill your subs eventually.

Putting 12's under the strut bar requires that you lower the floor at least 2 inches. There is only about 10" between the bottom of the STB and the stock floor level.