new box need some port help

[zdoc 0]

Im designing a new box for the new mag whenever it comes out and im going to stick my current sub in it for now (old 10" circle solo baric). I currently have it all figured out for 1.68 cubic feet. After the sub and port displacement that gives me the recommended 1.5 cubic feet with a 4 inch pvc port that is 19.12 inches long for a tuning of 32hz. Now my problem is that my box isnt long enough (20") for that lenght of port. Could I use 2 2 inch pvc ports each 9.55" to get the same tuning of 32hz? This will be going in my 05 king cab frontier so thats why im kinda limited on space. Also im thinking of putting the sub towards front of vehicle and port up, any advice there for in a truck?

Edited March 17, 2008 by zdoc

[audio-neon 34]

Im designing a new box for the new mag whenever it comes out and im going to stick my current sub in it for now (old 10" circle solo baric). I currently have it all figured out for 1.68 cubic feet. After the sub and port displacement that gives me the recommended 1.5 cubic feet with a 4 inch pvc port that is 19.12 inches long for a tuning of 32hz. Now my problem is that my box isnt long enough (20") for that lenght of port. Could I use 2 2 inch pvc ports each 9.55" to get the same tuning of 32hz? This will be going in my 05 king cab frontier so thats why im kinda limited on space.

Short answer- No.

Simplest solution, either use a joint for a bent port or have a couple inches sticking out the front.

The reason behind this is that the tuning is affected by the volume of air the port allows to move. area is pi(r*squared).

3.14x4= 12.56 per 2" pvc tubing

3.14x16=50.24" per 4" diameter pvc tubing

(simply put without going into the volume of a cylinder)

**I'm sure m5 or JimJ will be able to explain it better than I did.

[JimJ 11]

1) The port area of 2 2" ports is about half of a single 4"...

2) Personally, if I were you I'd go sealed with the new Mag. Would solve your space problem nicely, and the driver would be a lot happier. Just my opinion.