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DonH
12-01-2008, 12:07 AM
quick question. what are the benefits of an L shaped port? and how do you calculate the length of one side to another per say a port measuring 16.5 inches deep and you want an L shape to fire down. this is for a box im building. the box is 3.72 cubes after displacement and i want it tuned to 33 hz with a port that is 5x6. so i figure the port should be 12.4 inches long in total. how can i make this an L shape

IDSkoT
12-01-2008, 12:09 AM
L-shape helps accommodate a longer port while losing the least amount of air velocity.

To calculate you just figure out the port length and design... just make sure to measure in the middle. You could use the RE calculator if you want, or use WinISD.

dave_damage
12-01-2008, 12:10 AM
http://i36.tinypic.com/25p1mvn.gif

IDSkoT
12-01-2008, 12:12 AM
http://i36.tinypic.com/25p1mvn.gif

:yureawsm:

dave_damage
12-01-2008, 12:14 AM
:hide::hihorse:

DonH
12-01-2008, 02:08 AM
ok so going off of the re calculator here is my final design. had to go with a 2.5" width due to the depth needed for the subs. here is a top view of the box that is going in my ranger (downfire). its 3.3 cubes including port displacement so its tuned to 35 hz with 41.5 square inches of port area. thx


port view
http://img146.imageshack.us/img146/8648/realfinalportna9.png (http://imageshack.us)
http://img146.imageshack.us/img146/realfinalportna9.png/1/w640.png (http://g.imageshack.us/img146/realfinalportna9.png/1/)


finishd box painted
http://img141.imageshack.us/img141/5576/finalwithslotcolorcy1.png (http://imageshack.us)
http://img141.imageshack.us/img141/finalwithslotcolorcy1.png/1/w640.png (http://g.imageshack.us/img141/finalwithslotcolorcy1.png/1/)

IDSkoT
12-01-2008, 02:09 AM
Try to make the height of the lip at least 1/2 of the port width. (I.E. the space between the port and the floor at least 1/2... but preferably more. A lot more.)

DonH
12-01-2008, 02:11 AM
the port is gona sit 6 inches off the floor

Fusion_FREAK
12-01-2008, 02:12 AM
:yureawsm:

http://i62.photobucket.com/albums/h110/hewes18/gtfo.gif

DonH
12-02-2008, 02:43 PM
anyone disagree with the box i posted above?

DonH
12-05-2008, 12:27 AM
anyone check the box posted above

Alex JB
12-05-2008, 10:57 AM
Is your box going onto the floor (the extended peices being like legs) and firing down? Does the vehicle close one of the other sides?

If you are firing the port into the same airapace as the subs, with 3 sides enclosed, you may be filling in the airspace your subs left (as the cones drive into the box) with the exhaust from the port.
you thought about firing the subs down but pointing the port out of one ofthe ends of the box?

hatemonger
12-05-2008, 02:09 PM
Is your box going onto the floor (the extended peices being like legs) and firing down? Does the vehicle close one of the other sides?

If you are firing the port into the same airapace as the subs, with 3 sides enclosed, you may be filling in the airspace your subs left (as the cones drive into the box) with the exhaust from the port.
you thought about firing the subs down but pointing the port out of one ofthe ends of the box?

no. downfiring is fine. especially in extended cab trucks. he will lose output by pointing them to the side.

hatemonger
12-05-2008, 02:11 PM
my only question is. how much port area is it? and, what air space in the box?

DonH
12-05-2008, 07:22 PM
my only question is. how much port area is it? and, what air space in the box?

its 3.3 cubes with sub and port displacement and tuned to 35 hz . port area=41.5 square inches

hatemonger
12-05-2008, 08:56 PM
its 3.3 cubes with sub and port displacement and tuned to 35 hz . port area=41.5 square inches

looks good to me. should work well.

Rashaddd
12-05-2008, 09:30 PM
Is your box going onto the floor (the extended peices being like legs) and firing down? Does the vehicle close one of the other sides?

If you are firing the port into the same airapace as the subs, with 3 sides enclosed, you may be filling in the airspace your subs left (as the cones drive into the box) with the exhaust from the port.
you thought about firing the subs down but pointing the port out of one ofthe ends of the box?

when a sub moves outward, the air in the port moves outward, and viceversa. This is the whole point of porting, and happens most efficiently at the tuning frequency of the box

DonH
12-06-2008, 08:22 PM
n e more input b 4 the build tom.