Re: Adding port questions?
For one sd-2 10 sundown reccomends 1ft^3, so you should be fine with .9 but you would have to do an external aero port for each box.
The port would have to be pretty long though, if you did a 4" flared aero for each, tuned to 36hz it would have to be 27" long.
so you might be better off building another box.
This is a port good length calculator.
Car: Chevy Cobalt Coupe
Front Stage: Mids: Aura rpm 4", Midbass: Four Aura NS6's
Rear Fill: Pioneer 6x9s
Amps: 2 Rockford Fosgate T400-4's, and a T1500-1BDCP
Electrical: Stock 140amp alt, Big 3, and a SHURiKEN SK-BT100
Winter sub setup: Kicker F12a IB mounted from rear deck
In the works: Diamond D9 12