View Full Version : Advice for a sealed enclosure with 2 Type R 12s?

08-20-2011, 10:37 AM
Hello all!!

Great forum you have here!! I'm trying to learn all that I can, as I'm still a novice in this car audio world.

I was wondering if any of you could give me some advice on creating a sub enclosure.

Here's what I'm working with:

2008 Pontiac G6 coupe. I have 14" if vertical space to get the box tight up against the rear seats in the trunk. Due to space constraints, and more importantly keeping the wife happy, I will be going with a sealed box.

I have 2 2ohm Type-R 12's (SWR-1223D) with an Alpine MRD-M1005 amp.
In summary, the amp is rated at 1800 max, with 1000rms x 1. These are probably quite optimistic #'s, but that's Alpine's claimed ratings.

I'll be running the big 3 kit with 1/0 wire, which I know is overkill for what I currently have, but like like many of you here, I'm hooked on this stuff, and I WILL be upgrading eventually

To get the smallest footprint, mounting the subs vertically seems the way to go. I was thinking one fires forward into the back of the seat, wile the other faces rearward towards the trunk. What do you think of that arrangement? This still allows me to use half of the folding seat area if we need it hauling stuff.

I guess my main questions to you all are;

1. Is the .90ft^3 that Alpine recommends per 12" sub in a sealed enclosure the correct size? sound?
2. Should I separate the the 2 subs from each other with a baffle in between?
3. Should I double up the layers the sub screws into like I see many of you doing on here?
4. What is the best glue to use?
5. Is the 3/4" Mdf board you buy at Lowe's or Home Depot the right stuff?
6. Is 12ga speaker wire adequate?

I want to do this right, and appreciate you guys sharing the right plan with me.

Thanks a lot,

08-21-2011, 10:09 AM

08-21-2011, 10:35 AM
well, the only thing that does not sound good to me is the firing. they should both fire to the rear of the trunk, imho. firing one at the seat will have cancellation from the other. aqnother option, is to mount them at the rear corners of the trunk, in the space from the wheel-well to the rear of the car, firing at each-other. that usually comes out nicely. if you want some real output, vented enclosure will be nice, all firing rearward, from the back of the seats. however, sealed will get you some better flat response, and you mention the ability to fold a seat down for cargo, so i vote tward 2 separate boxes in the corners. and, yes, it is always good to separate the chambers to each sub..

08-21-2011, 10:56 AM
I'd go larger than .9ft^3 per, 1-1.25 would be more ideal. Yes to seperate chambers if sealed. Yes a double baffle would be good. Fire both rearward imo. Yes 3/4" mdf is fine, yes 12ga wire is good, use tite-bond or liquid nails or equivalant.

08-21-2011, 11:08 AM
If your worried about needing the space for various types of hauling, then just use some terminal cups to help with removal. It is a sealed enclosure with a couple lighter weight subs in it. Shouldn't be to bad on sliding it in and out a few times.

As for sub placement, I would fire both subs in the same direction. You can slide it in the car with them firing forward to see how it sounds, then flip the box around to having the fire back and see which you like better and go with it.

08-22-2011, 10:00 AM
Thanks for the responses!!

Looks like a removable unit will the solution here. That will keep the wife happy wheb she needs the car to haul a bunch of stuff. I should have known setting the subs firing opposite eace other was a bad idea.

Now since the box is already going to take up a larger footprint than I had originally wanted, should I just go with a ported or bandpass enclosure?

I previously had this setup in a Intrepid with a ported box. Unfortunately this box is too large to fit in the G6's trunk.

Thanks again for your input guys ;)

08-22-2011, 10:14 AM
i personally would. ceterfire slot all firing rear, but the wifey might not be keen on moving one big box. figure out how you would like to arrange the box, or boxes to keep them movable, and go from there. slotted is always nice and efficient

08-22-2011, 10:51 AM
No she wouldn't!! lol It would certainly get left on a street corner somewhere if I asked her to take it out.

I'll have to do some figuring on dimensions. The height can't be over 14", so it can at least slide up tight to the back seats.

I am getting a ton of rattling from inside the car. (with just the one sealed 12 I have running right now) It's the rear deck cover that fits up against the rear window, on top of the the 6x9s. It's kind of like a carpeted piece very dense cardboard. (not sure the name of this piece)

What have you guys done to keep this piece from rattling?

08-22-2011, 10:52 AM
running just one in a rear firing ported box might be a good option for you.
Then you can fold the seat down still on one side.
Let me tell you that removing the box so she can use the car will be a PITA for real , plus one day with the box out the speaker wires will touch each other and you better hope the fuse blows and not the amp.

1 - 12 in a good HO ported box will have a lot of output and be a happy medium.

08-23-2011, 12:10 AM
well, the rattling could be coming from the 6x9's as well, are there buckets intalled under them?

08-23-2011, 04:12 PM
Great news!! My ported enclosure out of my old Intrepid fits into the G6. Woohoo!! I played with the gains a bit and she is hitting pretty hard

This is great until I get some REAL gear installed. The biggest issue I am having is with the wife. She hates all the bass, so I have been unhooking the av cables to the amp when she is using the car. I wait to disconnect until the power has stopped feeding the amp, and it shuts off.

I need a real amp with a control knob NOW!!! lol

What do you guys think of either the AQ2200 or the SAZ1500 to run 2 quality 12's in an enclosure to be designed later?

Here's a couple pics:

In response to Akheathen, it's not the 6x9's rattling. It's this factory carpeted cover piece rattling. When I get back up in the window (with music loud) & hold it down, it sounds much much cleaner. There is a plastic housing that surrounds the tail light. I think this is making the most noise against the window. No there are no cups on the bottom of the factory 6x9s. Not a big deal as these will get replaced down the road.

Do you guys put anything under this piece to help keep it from rattling against the car subframe? Carpet or any sort of carpet pad?

I will need lots of deadening, as even this current gear setup is rattling the hell out of the trunk & body panels.