2 12's vented, or single 12 4th order BP?

[island boyeee]

I've been out of the game for about 10 years now, but used to do some competitions and build stereos for friends. So I'm trying to relearn what I used to know, and possibly expand my horizons a little with some new stuff.

As the title states I'm considering a couple options for my 2006 Subaru WRX. Unfortunately the trunk opening isn't huge, so I can only finagle about a 3 cu.ft. box into the trunk opening. However, if I built 2 separate boxes, I may be able to get closer to 3.5 cu. ft. by being able to slide them in separately. My dilemma here comes, that the main goal is to seal everything off from the trunk, but trying to face the subs and ports forward is going to be near impossible with about 32" of width in the seat opening (can't really go wider than 30" with one box and still be able to slide it in).

I guess finishing assembly in the car could be an option, but since I do race/auto-x every so often, it would be ideal to be removable.

SO, on to the meaty stuff. The subs I'm considering are either 2 12" RE Audio SEX V2, or 1 12" RE Audio SXX V2... My initial intent was one big box with a divider and everything facing forward. Well, since I found out I'll be pushing the limits to even get close to 1.7 cu. ft. per sub (more realistically, 1.5 cu. ft., after account for port and sub), I started to wonder if just doing one beefier sub may be a better option.

This is when I remembered that 4th order BP boxes exist, and I always wanted to try one. This would also be ideal if I could line up the port with the ski hole in the middle of the rear seat, allowing me to keep the seat in place if I choose. Either way, there will be a board sealing off the trunk that I would bolt the box to (with an opening for the port, of course).

I'm going for SQL here: I don't need all out bass like I used to, but I still want to be one-up on the trunk-thumpers (hence sealing off the trunk, which is practically made of tin on my car). I figure with this bigger sub in one properly built box, even if that means just a regular vented design, that I could be as loud or close enough to the 2 12's in mediocre-sized boxes.

I'll stop rambling for now, hopefully this is enough to get a solid conversation going. Any more info needed please ask. I would love to make this decision soon as the bug has bitten me hard and I'm ready to get back to building.

Thanks!

-Ian-

[Joe X]

Same power on twice the cone area is likely to get you better output, to me it comes down to driver selection, for example a SQ leaning driver that works in a small box could be JL 12W6v3 1.3 - 1.5 net, having a 4th order BP with one 12 to overtake in output and sound quality a two 12 " driver ported box would be rather difficult, I always recommend to go the simplest viable way first.

[island boyeee]

Understandable. I guess part of this came from being excited about the idea of trying out a 4th order after all these years. Although I'm not too familiar, so perhaps I thought they were more of a solution, than an unnecessary problem.

I have a Kicker SX1250.1 to play with, for which the birth sheet shows somewhere around 1,350 watts.

I'm open to other speaker suggestions, I had just decided on the RE Audio SE about 8 years ago when I started this, and am just now coming back to the project.

There are two main problems with 2 12's though (of course different subs might alleviate some of this)... One is that I can't really get more than 1.5 cu.ft. per sub for a single box with divider, and not much more than that for 2 individual boxes. The second problem is that even with one big box, I can't fit more than MAYBE a 3" wide port for each enclosure and have everything facing forward. That will probably be reduced to 2.5" wide per port if I have to do 2 boxes.

So if you're saying a 4th order is definitely out of the question for a stronger 12", do you think it's worth it to do everything I can to cram 2 12's in there somehow with less volume each? Or would doing the stronger 12" in a bigger enclosure be worth it?

I'm willing to sacrifice a few dB's for lower extension. I'm mainly a rap/reggae-danchall/hip-hop listener, and I really like my lows. My previous box builds many years ago were never tuned above mid 30's.

[Joe X]

It would be best if you provided your max dims for a box, that always helps with ideas, anyways if going for the lows on a single 12" leaning sound quality, you can use a single Fi SP4 12" in a 2-3 net ported box, it's just that the sub wants some 3KW if you want to get the most of it.

[Solo008]

I have a JL 10w6v3 in a small 4th order BP .45 cubic ft sealed-.45 cubic ft ported 1000+watts sounds great in my 08' wrx. Tried several boxes before finding this performed the best in my car with my setup. Very flat curve from 30hz-70hz.

[Wasteland_Audio]

It sounds to me like you would be a lot better off with 2 10s. That would make the 3ft^3 you have to work with go a lot farther, plus then you would be able to make a forward facing baffle a lot easier.

[island boyeee]

I'm definitely sticking with the one SX1250.1, so more power isn't an option for me. I'm not 100% opposed to 10's, but I'd like to make something work with 12's. I'm a 15" lover at heart, so I'm already crying a little inside.

I came across AD after remembering a friend had a cool build done last year. They have some pretty awesome looking stuff, and I had a great talk with one of the employees today. Might be switching brands.

They have two new lines of subs specifically built for 4th/6th order BP's. I may have them help me determine what enclosure would work best for my car and come up with the proper design for the proper sub, which may just be a regular vented box. Thy have a bunch of awesome box designs for specific cars on their website, many with a center front-firing port and the sub(s) mounted to the side. They will help me design a box mapped specifically for my car cabin if I go with them, so that's a huge selling point. I'm thinking one of their 3000 series 12" in a vented box may just cut the mustard.

I'll report back more on this after I follow up with them. I'm still completely open to all educated input.

[ShadeTreeMechanic]

I would run the 2 12s. Even if the box is slightly undersized. No divider common chamber single port. This will allow the port to be shorter and conserve more space than two chambers with separate ports. Make a card board box the same size to see if you can get it in the trunk.

[bman8891]

DC subs like smaller boxes Im running (2) xl12's in a 2.9 box and they love it. You should be fine at 3 cubes net. You can always use aeros too to limit port displacement

[island boyeee]

I would run the 2 12s. Even if the box is slightly undersized. No divider common chamber single port. This will allow the port to be shorter and conserve more space than two chambers with separate ports. Make a card board box the same size to see if you can get it in the trunk.

That's pretty much exactly where I'm headed now, thank you. I'm going to meet with a local dealer for AD tomorrow. They are going to take measurements for me, and then I will work directly with AD to figure out the best setup.

DC subs like smaller boxes Im running (2) xl12's in a 2.9 box and they love it. You should be fine at 3 cubes net. You can always use aeros too to limit port displacement

AD seems to be the same. 2 12's will work in about a 3 cu.ft. box with shared port.