i'm trying to design a sub box with 2 ports aiming straight up (will be aiming where 6x9 speakers here in my back deck)
the problem i run into is that with 3" round ports, my port velocity comes out around 28m/s and the lengths are 20" each.. which will not fit

i'm open to suggestions if anyone could help out

 

slot port it

 

i would, but being a fairly large sedan, i want to direct the ports through the holes where the rear speakers were

 

do you have a diagram to show what your looking for. Also box size and tuning freq.
If you're using pvc pipe for the port I would get some 45deg joints. 90s are too sharp. Also flare the ends to reduce port noise.

 

3" ports are not alot of good for anything over 8" subs.Try 4" or 6" at 12"long.How ever it is hard to say without sub size and box size

 

it's a 12" rockford fosgate t2, i ended up just building the spec enclosure for now

 

well for daily driver its likly best to stay with that, as RF do do some R&D for boxes to find the over all best box.
And 3" is real small for that sub

 

it's almost disappointing trying to make this car sound good and loud :P

 

Could you just do 4 ports instead of 2?

 

yes but they need to be a good bit longer to stay tuned the same
also leaving less box space or going to a bigger box