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View Full Version : Need help with ports, crew cab 2500hd with 4 E8v3's



Chaotic_Thought
06-23-2013, 05:41 PM
So i am working on my box to house 4 E8v3's under the seat of my 2007 crew cab 2500hd. The box comes out to 3.05 cubes gross before sub displacement and port displacement. My question is what to do about the ports. What would be the best route to go? I prefer aero ports because the less woodwork i have to do the better, and slot ports usually give me a hassle so i want to avoid them.

With that being said, what would be the best route to take? Here is a shot of the design. Pretty basic, nothing outrageous. If i need to get a little more volume i might be able to build a recess that will go up into the seat between the seat frame to add a little bit of space. I will be lifting the seat 2 inches.

http://i109.photobucket.com/albums/n69/dyabolical/rough2inchlift.png (http://s109.photobucket.com/user/dyabolical/media/rough2inchlift.png.html)

I am shooting for 35hz, so what would be the best option for size and quantity of aero ports? The box depth from front to back is 14.5" internal, so i guess i may have to 90 them to either side?

Thanks

PSturmer
06-23-2013, 09:09 PM
aero ports would be the way to go because a slot port would take up a lot of volume, and i would try to not go much below the .75 ft^3 mark per speaker. so you've go two options. the first would be to do the ports facing forward, but as you've stated your limited to 14.5" deep. 2x 4" ports would be too long, and the next size down would be 2x 3" port. to get 35Hz the 3" ports would need to be 9.25" long overall. the second option i can thnk of would be side firing ports. here the best route would probably be 1x 4" port firing out one side and another firing out the other side. this option would give you more port area, which is desirable if your running near or more than the recommended power to these subs. the question is whetehr the 2x 4" ports can fit in the box. if they can, and there is clearance on the sides of the box for the ports to fire (only a couple inches is necessary) then the ports would be 17 long, with a net displacement 2.8 ft^3, giving .7 ft^3 per sub. in this second case the tuning freq would be slightly higher at about 35.7Hz. the ports come 17" long standard, and i wouldn't recommend making it an inch longer to achieve that .7Hz decrease.

if you want to play around with the calculations yourself:
Products Menu (http://www.psp-inc.com/tools.html)

and the ports can be purcahsed from:
Parts-Express.com (http://www.parts-express.com/brand/precision-sound/285)

in your box design i would modify one thing also: add a small amount of support between the subs on either sides. when the would thins down it can get rather weak, and the being the baffle of the box, it is important that it stays sturdy.

Chaotic_Thought
06-25-2013, 05:58 PM
If i were to do the 4" ports, one per side, would it matter that each side of the tranny tunnel are slightly different in size?