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View Full Version : 18" BTL Box Design Critique...



SHiZNiLTi
01-17-2007, 03:17 AM
How do you think the overall design will perform in my blazer?
What would you do to prevent flexing?
Is there enough port area?


7.3 cubes ~ 31hz ~ 105sq.in. of port...
http://img126.imageshack.us/img126/9268/boxspecs18rk8.jpg

I can't believe I just spent this much on a sub...
http://img126.imageshack.us/img126/8194/fibtllk3.jpg

I've gone through alot of design's and I'm thinking about doing somethign like this..
http://img126.imageshack.us/img126/9600/18btlboxcw7.jpg

Please post up any other design's that you think would work out better for me.

Thanks!

geowick07
01-17-2007, 08:18 AM
1. From what i have heard and seen, you may be better off with the sub facing up in a blazer-suv setup. but, try it out and see what you think.
2. Personally, definitely double baffle, and some 1.5" wooden dowel side-to-side and top-to-bottom. Some will recommend all thread( threaded rod), but you will see the thread and nuts and washers outside of the finished box. Personal preference = wooden dowel.
3. Port area seems a little low, but that could be just the design of the box itself. And being tuned that low. Have a look at this. Subwoofer Enclosure Design (http://www.subwoofertools.com/forum/ported-box.asp?Ew=37&Eh=19&Dia=11&Xmax=27&Vd=.26&NumW=1&Vb=7.3&Fb=31&Qts=&Vas=&Fs=&CE=0)
I took the liberty of filling in your specs, and the dimensions stayed the same except for the overall depth of the box. It went up from 27" to 30". Don't know what your max dimensions are, but if i went over, feel free to play around with that box calculator til you find something that works for you. But, if you are set on that box you designed, it should be fine.

angrytrucker78
01-17-2007, 08:33 AM
27 inches deep with a height of 19 is pushing it to begin with in a 2 door Blazer. No way 30 is gonna fly.

rpfuror
01-17-2007, 10:14 AM
LOL, that 3d drawing is a box I designed that was 11 cu/ft @ 32Hz,

If you what something custom for you application let me know;)

Goldtaz1
01-17-2007, 10:43 AM
PM sent dude.

SHiZNiLTi
01-17-2007, 04:54 PM
Has anyone tried sub on top with a vertical port?

http://img110.imageshack.us/img110/159/18btlboxcw7cn2.jpg

rpfuror
01-17-2007, 05:05 PM
I done it.. in that case I would typically build the box in a CRX design.

j3bus2k3
01-17-2007, 05:07 PM
That RE calc is flawed. It does not take into account driver displacement...

Do sub up, port back with about 120sq.in. of port....

SHiZNiLTi
01-17-2007, 05:38 PM
That RE calc is flawed. It does not take into account driver displacement...

Do sub up, port back with about 120sq.in. of port....

Thanks for info j3bus2k3, I was just using that RE calc as a quick guide to work off of. I've got an expereinced box builder helping me out with the design now. I'll post up a work log soon :D

angrytrucker - 30" would still fit, but I would only have about 2" between the port and rear hatch which is no where near enough space, thanks for catching that though and making me re measure everything.

I'm going to go with these measurements:
37W x 18H x 26D

Port Dimensions:
16.5"H x 5.5"W

Port Length:
29"

Tuning:
32hz

saywhat?
01-17-2007, 05:39 PM
6 cubes @ 33. crx style

/thread

SHiZNiLTi
01-17-2007, 05:50 PM
LOL ... /Thread - add the port area in there. Why do some people say 120sq.in. others say 90sq.in.?

If more port area makes it louder then why wouldn't everyone try to do the max port area?

after this question we can do a /thread :D

mazdakid
01-17-2007, 05:59 PM
because the more port area you have the longer the port has to be to stay tuned low

mazdakid
01-17-2007, 06:01 PM
if you went with 6 cubes then 80" of port would be enough

saywhat?
01-17-2007, 06:23 PM
6 cubes......100 sq inches......33hz. hit me up for a design if you need one. Id be more than willing to throw something together that would even look good ;)

bamaboy
01-17-2007, 06:25 PM
do 15 sq in per cube, good rule to use

SHiZNiLTi
01-17-2007, 06:26 PM
Perfect, thats what I'm at for port area.

Thanks guy's. This is going to be one hellova loud **** shiny black box when Im done with it :D

angrytrucker78
01-17-2007, 08:10 PM
angrytrucker - 30" would still fit, but I would only have about 2" between the port and rear hatch which is no where near enough space, thanks for catching that though and making me re measure everything.

I'm going to go with these measurements:
37W x 18H x 26D

Port Dimensions:
16.5"H x 5.5"W

Port Length:
29"

Tuning:
32hz

No problem. I have a 2 door Blazer as well. My dimensions were 38x15.5x27. Fit under the window line, and was able to lock the seats back into place. Couldn't get my hand under there to release them though.