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JimBo930
04-30-2006, 04:41 PM
Ok i bought a 10" type r, and i was going through the manual to see what specs the box i am going to make should be. It says the vent lenght should be 22 in, but the recomended external box dimensions should be 12.5" x 14.5" x 17.25", my question is how is the vent supposed to be 22 inches long when the box is not even 22 inches long:eyebrow:

PowerNaudio
04-30-2006, 10:11 PM
you have to use a slot port and fold it.

revrider1
04-30-2006, 10:12 PM
Slot ports.

James Bang
04-30-2006, 10:30 PM
nvm

JimBo930
05-01-2006, 04:21 PM
So for example....

http://img62.imageshack.us/img62/3228/16cubes32hz25sqin9rn.th.png

Or....

http://img62.imageshack.us/img62/7482/125cubes32hz21sqin4qf.th.png

Which one would perform better?
Or will they perform the same?

watts
05-01-2006, 05:43 PM
It doesn't have to be a slot port it could round with a elbow. I would be careful the actual box volume should include the volume of the magnet and cone structure along with the volume occupied by the port(The manufacture estimated this for you when he gave you the dimensions). If you build an enclosure with a slot port that is made from a thick piece of wood it will change the recommended volume. Keep in mind the manufacture has just given you three numbers that simply corresponds to the required volume you can squish those numbers any way you want as long as the box volume doesn't change.

For example you have

12.5*14.5*17.25=3126.562 in^3

convert to ft^3

3126.562 in^3/1728=1.79 ft^3

By changing the dimensions.

10-3/8*12*25=3112.5

convert to ft^3

3112.5 in^3/1728=1.80 ft^3

Now you have room for your port but you haven't changed the volume of the enclosure at least enough to make a noticeable difference.

JimBo930
05-01-2006, 06:18 PM
Ok ic what your saying, but my trunk space is forcing me to do something other then a straight port. The Dimensions i am working with are 28" Wide, 11" Depth, and 11" height. And the Port/vent length required is 22"

Forgot to mention that this car is an 84 Firebird, which should give you a better idea on what im talking about.

watts
05-01-2006, 07:12 PM
I would go 25-1/2 by 11 by 11 and port in the side. Try to make the end of the port free of any obstructons outside of the enclosure. Try to leave a space away from any walls or windows in the car. I have a ten inch type r in my jeep my enclosure is a little smaller than what is recomended by Alpine and it hits nicely.

(25.5*11*11)1728=1.79 ft^3

You would still be OK.

JimBo930
05-01-2006, 07:21 PM
So having the port on the side of the box wont hurt the enclosure? I always thought that it should be facing the same way as the sub.

watts
05-01-2006, 07:35 PM
I would be sure didn't rest against any of the enclosure walls. In the SPL world you try to place the ports in the same direction of the subs and space them from each other based on the distance from the mic placement area to the end of the enclosure to avoid wave cancellation in the cab resonant frequency. Take a look home theater and bandpass enclosures. It shouldn't be an issue.

JimBo930
05-01-2006, 07:43 PM
Alright thanks alot