Alpine Type R Enclosure

[GorillaFIngeRs]

I know there is probably a thread for this already but i couldnt find one. I am looking to build a ported box for a new type r swr12d4. I have a box currently but I dont really trust it since it ruined the last alpine I had. My girl got this for me for christmas cause she knew i blew mine haha. I would just like to build a nice box for it now and am looking for some help. I've read that most people run them around 2sqft. Spec calls for 1.75. I am open to any of your guys suggestions. Trunk space i can give up is 15"Hx32"Wx17"L. Looking to tune around 32hz. Thanks guys

[Joe X]

Ok there's a spec confusion between older Alpine subs and 5th generation ones, recommended net volume for the older SWR-1243 and previous ones are 2.0 cubic feet for the SWR-12D2/D4 is 1.5 cubic feet placing these latest subs in 2 cubic feet will result in a less musical peaky response that some maylike, some not, anyways here is a couple of suggestions, the proper box and the larger peaky one, both within the requested maximum dimensions.

NOTE: Sub /port aimings adequate for trunk cars.

NOTE: power: to 1000 RMS, amp subsonic filter to 28Hz, minimum port clearance 2 1/2", figures are just an assembly guides.

NOTE: If building outside you need to build a cardboard dummy box to test fit in it's way inside.

Suggestion 1: Larger box peakier performance, higher efficiency:

Suggestion 2: Maximum recommended box size, better musical performance, standard efficiency:

[Blaze92]

Back when I had the same sub as you I used the cutout dimensions that Alpine supplied on they're website under the tab for this sub. It sounded very clean and decently loud too for a single 12. You can always build it a tad bigger than specs to get more bang.

[Joe X]

Back when I had the same sub as you I used the cutout dimensions that Alpine supplied on they're website under the tab for this sub. It sounded very clean and decently loud too for a single 12. You can always build it a tad bigger than specs to get more bang.

The name of the game.

[James Keaton]

I am trying to design a dual 12" enclosure for my 1243D Type R 12's. I have attached what I have come up with so far. According to Alpine the port volume and the internal net volume are almost exactly what they need to be. Everything will be 3/4" MDF except I added a 1" panel to the front just so I can recess the subs to make them flush. I have encluded some of the specs. I am trying to figure out what the box would be tuned to.

[Triticum Agricolam]

OK James. First off, you should create your own thread for this instead of hopping onto someone else's.

Second off, that piece separating the two ports in the middle of the box does nothing for you but take up space. You can remove it and make your box 3/4" narrower.

Lastly, for reasons I'll never fully understand Alpine recommends really bad port dimensions. With their specs you end up with barely half the port area you should and having the port be that tall and narrow makes it very inefficient. But I can answer your tuning question, if it is done exactly to Alpines specs it will be tuned to 36 Hz.

My recommendation is your change your box to have about 30 sq. in. of port area per sub, get rid of that center divider, and tune it to 32ish Hz.

[James Keaton]

OK James. First off, you should create your own thread for this instead of hopping onto someone else's.

Second off, that piece separating the two ports in the middle of the box does nothing for you but take up space. You can remove it and make your box 3/4" narrower.

Lastly, for reasons I'll never fully understand Alpine recommends really bad port dimensions. With their specs you end up with barely half the port area you should and having the port be that tall and narrow makes it very inefficient. But I can answer your tuning question, if it is done exactly to Alpines specs it will be tuned to 36 Hz.

My recommendation is your change your box to have about 30 sq. in. of port area per sub, get rid of that center divider, and tune it to 32ish Hz.

Thanks for your reply. I wasn't trying to hijack the OPer's thread, I just didn't want to flood the forum with a question related. Sorry about that.

I always thought that the port divider made a difference, and the port or box isn't built to specs with Alpine's suggestions.

Lastly, for the port area, if I remove the divider and reconfigure the box/port I can get the port area to 59.5in^2. The port would be 14 x 4.25. Also, how do I know when an enclosure is tuned to 32Hz? I have tried to research this and the only thing I have is everyone is saying to build the enclosure and play with port length. Do you have any better recommendations for this?

[Triticum Agricolam]

Thanks for your reply. I wasn't trying to hijack the OPer's thread, I just didn't want to flood the forum with a question related. Sorry about that.

I always thought that the port divider made a difference, and the port or box isn't built to specs with Alpine's suggestions.

Lastly, for the port area, if I remove the divider and reconfigure the box/port I can get the port area to 59.5in^2. The port would be 14 x 4.25. Also, how do I know when an enclosure is tuned to 32Hz? I have tried to research this and the only thing I have is everyone is saying to build the enclosure and play with port length. Do you have any better recommendations for this?

Tuning is a function of port area, port length, and net internal volume of the box. You can learn about the formula here http://www.jlaudio.com/header/Support/Tutorials/Enclosure+Ports/Tutorial%3A+Enclosure+Ports/287541

Or if you just want a calculator to help you get the answer you can do that here: http://www.carstereo.com/help/Articles.cfm?id=31

[GorillaFIngeRs]

Back when I had the same sub as you I used the cutout dimensions that Alpine supplied on they're website under the tab for this sub. It sounded very clean and decently loud too for a single 12. You can always build it a tad bigger than specs to get more bang.

The name of the game.

This comment makes me wonder if i should be going for the larger box.... What do you recommend? I do drive a lot and listen to hip hop mostly. I just want to have the best boom i can. I have a MTX sub in my house and am jealous of how that thing sounds i wish my sub in my car could produce such clean bass, so whatever would get me closest to that I guess.

[Joe X]

It's a matter of personal taste, some people will like peaky some not. The smaller box will sound a bit cleaner.