18" BL fully loaded questions

[codypt 0]

I am thinking about getting an 18" BL for my 98 pontiac grand prix gt sedan. My car has a big trunk and I think it would be big enough for this sub and a good size ported box. I was wondering if anyone would have any advice as to whether this would fit fine and also amp recommendations? I would get the daily driver option as well. Im thinking around $400 for the sub and I could possibly build the box with my dad. Also what would be a good cap to go with it and would there be any other modifications I would have to make to my car's electrical system? I already have an alpine head unit.

[Sir-Lancelot 216]

Problem you will have is you will have to fire it up to the trunk lid, I bet.

You would be better off firing 2 12's to the rear.

[bassahaulic 155]

The electrical is completely dependent on how much power you run form your amp/amps, not on the woofer you have.

I support the 2 12"s idea, would do much better then trying to squeeze that 18" into 4cubes.

And get the capacitor idea out of your head now. Lol

[NB50 206]

Unless your going to build the box in the trunk, you are not going to get the airspace needed for an 18" sub to fit through the trunk opening.

[BanginGMC 23]

(2) 12" BTL's.

Rms: 2000W * | 2000W *

Sealed box: N/A cuft | N/A cuft

Ported box: 1.75-3cuft | 1.75-3cuft

Sub OD: 12.500” | 12.500”

Cut ID: 11.125” | 11.125”

Mounting depth: 7.250” | 7.250”

Displacement: 0.18cuft | 0.18cuft

[codypt 0]

I just measured my trunk, its not square, but I measured the most narrow parts. Its about 3 feet wide, 4 feet deep and 20 inches tall. I could easily fit a 12 cubic foot box with room on the sides. I also rounded down. My trunks big, when I say big, I mean i had an 8 person tent in the back not folded up along with two 33 gallon trash bags full of clothes with my friend in there who weighs about 170. (Dont ask why he was in there hahah)

Theres also a thing in the middle of my backseat that comes out and would allow instant access to all the air in my car when opened. If im calculating the cubic feet correct, I could easily get over 10 feet which is more than recommended. Hope that helps, and my goal is to have something that bangs hard, while sounding good. And my budget is around $700-$1000.

[mikey5472 16]

2 12's. You will be happy. More motor strength and almost as much cone area.

[NB50 206]

I just measured my trunk, its not square, but I measured the most narrow parts. Its about 3 feet wide, 4 feet deep and 20 inches tall. I could easily fit a 12 cubic foot box with room on the sides. I also rounded down. My trunks big, when I say big, I mean i had an 8 person tent in the back not folded up along with two 33 gallon trash bags full of clothes with my friend in there who weighs about 170. (Dont ask why he was in there hahah)

Theres also a thing in the middle of my backseat that comes out and would allow instant access to all the air in my car when opened. If im calculating the cubic feet correct, I could easily get over 10 feet which is more than recommended. Hope that helps, and my goal is to have something that bangs hard, while sounding good. And my budget is around $700-$1000.

And try to fit a box that size through the trunk opening, not gonna happen. You will have to build in the trunk to do it.

[codypt 0]

Building in the truck would not be a problem at all. The trunk part that opens goes all the way to the glass of the back windshield which is rather strange for a car. The problem of 2 12s would be the cost, for practically the same price I could get an 18 BTL. But I at least want two 15s. I was first thinking of 2 alpine type r 15" but i found out about FI and heard they are better speakers all around. And I do know type r is a more SQ sub than SPL.

[mikey5472 16]

There is no way you can build a box that is going to just slide in for a 18. Or 2 15's 2 12's or 1 15 would be you're best bet. And I've never heard of type r's being a sq sub. In the right application maybe.

[codypt 0]

Type r is more of a sq sub than say for example kicker... And if I cant get an 18, then Im going to go with two 15s. The main reason I wanted the 18 is cuz I heard one and it banged, and also I would save around $200 on the subs themselves.

[ralstonballa2413 20]

You will have to build the box in the trunk if you are going to go with this option and you need to make sure that you can still get the sub in there once it is built. You would be much better off with 1 15" or 2 12". Its going to take much more work than you think it will.

If its haed to fit 1 18" then it will be even harder to fit 2 15". We are all trying to help you make your setup better and that means you need to give it the proper amount of air space in the box and also around the box.

Edited May 7, 2010 by Miller

[mikey5472 16]

2 15's will take just as big of a box as the 18. I'm telling you get 2 12" bl or ssd btl q whatever you prefer and run it of the recomended power do you're big three upgrade batteries and you'll be happy. Just because you heard a 18 in someone elses car and it banged doesn't mean its going to do the same thing in you're grand prix. Trust me and all the other people that said 2 12's. It is you're best bet with getting loud while not having to build a box in you're car.

[codypt 0]

I know man, I appreciate it all. I just dont want to spend a ton more money than I could for similar results. Say for example I go with the 18, the mounting depth is about 10 inches. So I assume its definitely possible to have the sub facing upwards in a box thats about 2' by 3' by 15". My concern would be if it would sound weird facing up instead of out???

[mikey5472 16]

Even if you do get that 18 in you're car it won't have room to breath. All the air being pushed by the sub won't even make it in the cabin. Actually I have a good example I used to have a 18" bl and my buddy had a 15" bl same power same amp same h/u same everything. He had the 15 in his car while I had my 18 in my Jimmy, his motor cracked on the 15" and I had sold my amp so we built a box for the 18 INSIDE his car. To specs, buuutttt it sounded like complete ass and wasn't as loud as the 15. You know why? Because the sub was being choked it didn't have room to breath.

[NB50 206]

IMO and experience with that body style of grand prix either two 10"s or two 12"s. Anything bigger and you are running out of room for air flow and flexibility of box design.

[codypt 0]

Alright I guess I'll stick with two 12s. But what box size/design would work well? And what are some good amps to match up with it?

[NB50 206]

Its been awhile since I've had a ported box in my car but IIRC the dimensions where 32"W X 21"D X 14"T. I think you could take it to 35.75"W and still be safe getting it in the trunk. I should go out to my car and figure the dimensions cause I was going to build another ported box but I'm lazy, its raining, and the box in there is to heavy for me to dick around with right now.

[codypt 0]

One last question. What would be louder and sound better overall, a single 15 btl or two 12 bl? And would the 15 fit a lot easier than the 18?

I ask this because two 12 bl would be $550 and one 15 btl is less than $400. And they would take about the same amp..

[NB50 206]

IMO to do a 15" in your trunk it would need to face up. If it faces the rear the size of the box traps the sound in the rear cavity and doesn't allow the sound to move into the cabin, at least in my experiences.

[smashedz28 110]

I got a friend who has a grand prix.. And since I have a btl 18 in my tahoe I see no way in hell that an 18 btl will fit PROPERLY in the trunk. I built a box for my friend to hold 2 12's comfortably and that was about all that was goin in there. Hell the box my single btl 18 is in now probably wouldn't even fit across his back seats. Lol, listen to these guys here, they know what there talkin about. 2 12's can hit real hard if you got the right equipment ( Fi ) and a good installation

[ssh 924]

It' seems to me that you want to ignore everyone's advice and stick a 18" in your car... People are trying to help you, not talk you down.

[Kent535 25]

Lets See Pics Of That Trunk. Id Like To See How Big Your Talking About When You Say "BIG"

[codypt 0]

Well I've already decided on a 15, but I'd be more than happy to show pics, but do I have to upload them to photobucket or can I just save them on my computer and upload them like that?

[ssh 924]

You could upload them to imageshack.us then post link here