View Full Version : 2 18" Sub box?

04-07-2009, 03:17 AM
I am about to install 2 18's in the back of a Gmc Sierra Ext. Cab. I will be taking the back seat out. My question is should I have the subs and port facing up or Subs facing forward and port up. I was told to have the subs facing forward and port up but I would like more opinions on this.


04-07-2009, 03:33 AM
Just throwing this out... Subs forward, port forward.
Subs up, port to the side

04-07-2009, 03:37 AM
i have one 18, sub up, port up. idk how well that would work for two eighteens tho

04-07-2009, 01:34 PM
Anyone else.

04-07-2009, 02:49 PM
both forward or both down

04-07-2009, 03:00 PM
If your port is not up, make it as close to the floor as you can.

04-07-2009, 03:01 PM
people in suv's normally go sub up port back (from what i hear)
extra cab trucks are pretty box shaped so idk. i dont think my **** would be as loud with port up and sub up..

04-07-2009, 03:04 PM
Loudest I believe is port side sub forward or up, but I doubt you can do that with 2 18"s.

04-07-2009, 03:04 PM
Subs forward, port forward on drivers side...ftw..

04-10-2009, 11:17 PM
Any other suggestions?

01 S 10
04-10-2009, 11:22 PM
wall it, subs forward, port foward

do you really have 12 cubes net available in a "regular" box? you may need to wall it off anyways

04-11-2009, 03:51 PM
Hunter on here has 3 subs forward and port up

04-12-2009, 07:01 PM
wall it, subs forward, port foward

do you really have 12 cubes net available in a "regular" box? you may need to wall it off anyways

With the measurement I did I have about 19 C.F. Gross to work with. But I want 13 C.F. net.

04-12-2009, 07:05 PM
Sub and port up will cause cancellation, and you'll notice that you're a good deal louder when you roll a window down or crack a door open. I've found that sub foward/port up works great. I'd assume sub up/port forward would basically do the same thing. I've never tried firing the port to the side...my ports are generally to long to do something like that, since I like to tune in the low 30's with a good deal of port area, and I end up with a 20-30" long port.

04-12-2009, 07:10 PM
How much port area should I have? I want it tuned to 32Hz also.

04-12-2009, 08:26 PM
I know alot of loud ext cab guys who run subs up and port at the very bottom driver side, firing into the side of the car. That seems to work best.

If the port is pretty close to the side of the car, you can tune higher. It will load on the low notes giving you the lower bass, but because of the higher tuning you will still have the good output.