HELP!!! 09 M3 GT with 2-12" Alpine Type X's

[skallen]

As the title says, I have an 09 M3 GT Hatch and I want to put my 12 inch subs from my 02 Sentra SE-R Spec V in there. Alpine says the required airspace is to be between 0.7-1.0 cubic feet per sub for a sealed enclosure. That means 1.4-2.0 for both 12's. My calculations for my enclosure allow me to still flip up my in-floor hatchback tray at the farthest back of the car. If anyone knows if this is true, I would greatly appreciate it. I just wanna make sure I didn't screw anything up. I used the Rockford Fosgate Box Volume tool on their website. I want as much room left as possible. PLEASE, can anyone confirm this?????

 

[JUSPEED3]

not feally sure about the spacing but i have 1 "12" PIONEER PRO CHAMP SUB (ENCLOSED BOX) SOUNDS GREAT . had a rockford fosgate pw4 an it fryed same day put it in.it's lil tricky to get to spare but not difficult(squinty)

 

[skallen]

nobody can help me with this??? Please!!!

 

[skallen]

I just need to know if my box calculations are correct...The rockford fosgate website said the dimensions should be around 28" wide 15" high and 10" deep...That would give me around 1.76 cubic feet...These are outside measurements...That would make the airspace ideal for these subs. However, in my measurements in the car, the box seems to be quite a bit smaller than I expected. Is this right??? My calculations would let me have these 2 12's and still be able to flip up that rear storage space in the hatch...Can anyone please confirm this??? These are massive subs with big magnets. I AM DESPERATE!!!! I haven't had real bass in 6 months. This just doesn't seem right to me!!!!

 

[derspi]

I've never used that box calculator on the Rockford website but doing it the old fashioned way required that you take into consideration of the box wall thickness as the volume for each driver given is for internal volume. You also have to factor in driver displacement which is basically the space taken away from the sub basket and magnet when loaded into the box. You should take a look at the Alpine website instead, it should list an "ideal" box configuration based on your model of sub with all of those factors accounted for.

 

[UnZipHer15]

just switch to a JL Audio W7 driver with a triple wall enclosed box like me and you wouldn't have any problems!! what size wiring do you have running to your amp?

 

[skallen]

I don't have it installed yet... But I am using 0 gauge wiring, JL 1000/1 for subs and a JL 300/4 for Alpine Type R components...I want to use the smallest box I can so I can utilize some of the space in the hatch...A W7 won't offer me dick all for space

 

[derspi]

just switch to a JL Audio W7 driver with a triple wall enclosed box like me and you wouldn't have any problems!! what size wiring do you have running to your amp?

I don't see how this would help the OP.

But on a side note, the W7 is a good sub - just too deep and requires a fair amount of airspace so it isn't the most practical application for ppl who actually want to conserve trunk/hatch space.

 

[UnZipHer15]

good amp choice thats exactly what i have powering my W7 and 0 gauge is perfect you don't want to do any smaller or else you will starve your amp of power. you can get the W7 in a JL Audio box and it is not big at all. HEAVY AS HELL but i have alot of room. i'll take a pic tonight and post it tomorrow to show you!

 

[derspi]

you can get the W7 in a JL Audio box and it is not big at all. HEAVY AS HELL but i have alot of room. i'll take a pic tonight and post it tomorrow to show you!

I've seen that box, it's pretty damn big if I recall. But it could just be that my needs are different from yours.

 

[UnZipHer15]

your right! i thought i had more room in the back. i have the sub pushed to the right that's where i had the 0 gauge and remote and rca's ran too so i still have about a foot of room in the front of the sub and i have the entire left hand side. i forgot to take pics i'll try to get those out but maybe skallen should think about doing a stealth box or just throw the subs in a truck box and mount the amp to the back of the box. saves room and if the box is ported which is should be for 2 alpine 12's you'll have plenty of air space and room to even throw a cargo net in the back if you're into that sort of thing haha!