new box for alpine type r

Women Have Legs- width x height x length Width? 28" x Height? 16.75" x Length/Depth? 20" (external with double baffle on front) (port W?-2.5 x H?-18.8 x L?-35) So looking at the picture, is the 18.8 the top-bottom measurement? Its indicating the outside height is only 16 3/4, so that 18.8 cant be correct on the height of the port. Perhaps were thinking its(just as it sits in the pic) -2.5" wide -15" Height -??length?? hmmm 24 linear inches of your 2.5x15=37.5 <----the area of your port is that number. Each sub size pretty much has a general area, (slot or round) that you can reference to. The slot/port length is the keys to the instrument that allow a fellow to make some tuning adjustments if so inclined. Except when a fellows car is a little short on room. Dam, with 4 1/2 ft3 we could end the possibility it could be any better. Not to mention I was gonna bid 1" MDF. Have you tried the 15 sealed?This is what I do for FUN!

Port length from front to back = 13.5 Port length from left to right = 12.75 (All measurements are with the top On the box)UNLABELED Custom Car Club President

The way I have figured that will tune you to around 34.5Hz. A tad high for the results your looking for. Im getting 3.20cu.ft. net without figuring bracing or port wall. So you are right on the money once bracing and port wall are figured, but im only coming up with 29.5 port length. For a folded port you measure length in the center of the port. Taking into account bracing and port wall to get you to your 3.0 cu.ft, port 2.5 x 18.5 X 29.50= Fb of 34.5Hz Me personally I would do it at 30 square inches of port area for 3 cube. Its more than enough to eliminate port noise. Your last enclosure was using a 3in round port. Thats only 7 sq.in. of port area and the reason you had MASSIVE port noise. You essentially had a leaky sealed enclosure As for you earlier question, about port area. You want enough port area to be around 20m/ sec in your open civic. 30 square should more than do that eliminating port noise. Going to a too large port area can result in a very fast roll off and a peaky out put. Notice how comp vehicles have really huge port areas? Although there can be a gain in output it make it much more narrow frequency response. Thats why they call them burp boxes. Not ideal for daily listening.

Thanks A lot for helpin me out J.Reed. So I changed the port opening to 1.75" = 32.4 sq in port area port length one = 14.25 port length two = 6.75 (measured 22.5 total down the center on the port) This should be real close to 30Hz after Lots of bracingUNLABELED Custom Car Club President

blackcivichatch wrote: Thanks A lot for helpin me out J.Reed. So I changed the port opening to 1.75" = 32.4 sq in port area port length one = 14.25 port length two = 6.75 (measured 22.5 total down the center on the port) This should be real close to 30Hz after Lots of bracing

Yep bracing is your friend. Just remeber as you take away from your net it will raise tune a bit, so it important to account for everything as well as you can. Might take a few back and forth trips to the calculator, but the end result will be worth it. If i might make one more slight suggestion. See if you cant widen the port a bit more. 2.5 was good, you could shorten the height a bit to get it where you need it. So it important to account for everything as well as you can. may take a few back and forth to the calculator but the end result will be worth it. If you need or want a double check feel free to post it up.

I kinda wanted to keep the port the full height of the box for cosmetic purposes. But if you think there will be much of a difference, I can work somethin out.UNLABELED Custom Car Club President

blackcivichatch wrote: I kinda wanted to keep the port the full height of the box for cosmetic purposes. But if you think there will be much of a difference, I can work somethin out.

port area wise it is fine. I just think that 1.75 is a bit tight and could end you with a bit of port noise because of the narrow gap. You could do 2" x 17" that would mean just adding a strip of 3/4 to the top and bottom keeping it uniform. Not much of a change though. Thats only 1/4" more open for 34 sq.in. It could be fine by simply rounding over the edges of the port too.

I did plan to round the edges pretty good. (just dont know how to show that on sketchup yet lol) And the 2 x 17 seems feasible. Give me a few min to make the changes.UNLABELED Custom Car Club President

blackcivichatch wrote: I did plan to round the edges pretty good. (just dont know how to show that on sketchup yet lol) And the 2 x 17 seems feasible. Give me a few min to make the changes.

Well your better at sketch up then me lol. I just use photoshop and 2D it. Looking at your design I thought it would retain your look pretty well.

Ok. 2 x 17 x 26 long Net of 3.3 to 3.4 after Bracing. should be 29.5 to 30 hzUNLABELED Custom Car Club President