Any one running four 12's?

[tyler]

I'm stepping away from engine work for a moment and decided a nice sub set up would be a vgood change of pace. I have my plan all drawn out, measuments done, checked and checked again and decided on a fiberglass box with mdf framing. Now I've been building sub boxes since I got my license and have picked up a good amount of skill, at least with car trunks. I will be running 4 diamond audio 400watt 12's off of 2 jl amps that are rated at 500 rms true watts. My plan is to mount the subs up but slightly slanted so they all focus and the middle of the hatch and port the box towards the rear, roughly the area of the spare tire. My question is if any one has this many subs, is there a difference in acustics of the car since there is no barrier (ie seats) in the way? And wll this sub port set up be optimal?
As always thanks for ur input and any suggestion is welcom. But I am sticking with the diamonds and will upgrade to higher watt diamonds later on.

Tyler

[tyler]

Also for those of you that do a lot of fiberglass work would you recomend cutting the mat into strips or just tearing it apart so that I'm left with loose fibers. There has been some debat over this with a co worker of min.

[Monkman33]

Since you have no barrier to really diminish the power, my personal preference is a sealed box for fidelity. As for strips or tearing, i use strips except in tight spaces where I end up tearing the strips into smaller pieces to fill in the tight spots.

[tyler]

Very true but I want as big of a boom as possible, I had two of these subs on a 450 true wat amp and it poped the trim off of my cirrus,

[Monkman33]

cirrus/neon = trunk mounted (also rattle boxes lol)

Unless you are pretty decent at making a ported box that has the right volume and port size/length/placement, then I would stick with a sealed box. You're talking about the interior of an rx7, with no seats to deaden the volume at all.

Personally, I like sealed boxes for their simplicity and fidelity, although fidelity is obviously not your goal. However, you wont have any problem with volume since the subs are literally sharing the same airspace as your head. I just don't see the point in going for every ounce of spl in a car where you are going to supposedly listen to the music.

[tyler]

This is my second "boom" set up I've made (first for personal use) and I wire the subs in sets and run them off switches in my dash theat connect to the rem for each set, that way I have control over spl while driving and also a the car shows. From what I've seen ported boxes are a little more forgiving when it comes to volume and as for port size I have a program that calculates port size based on sub and box dimensions this way I can tune the box to what ever freq I need. But with this being a fiberglass enclosure ill have to resort to the old packing peanut method to measure internal volume which is a little less then precise.
I see your point about the strenghts of a sealed box and how it can be pointless to have thiis much bass in such a small car but why not? As long as I have the switches to make it bearable to drive( and legal) then I figure ill "go big or go home". The diamond audio's I have produce amazing sq while still pounding so driving with 2 on should be more then enough and the extra 2 will be when. I wana show off

[tyler]

And thanks for the info on the fiberglass strips, I forgot to thank youfor that in previous posts