so im looking at building a box for my 06 crew cab silverado. i plan on putting them behind the rear seat. does anyone know if it is better to face the subs against the rear wall of the cab or should they be facing the inside of the cab? i know in cars you will get the most out of your setup if you face it towards the trunk lid because it reflects back into the car IIRC. is this the same in this situation?

 

The idea behind pointing a sub box to the rear of the trunk is to try to do what is required to propagate a bass note.
1) wavelength, the longer the length of the bass note to your ears the better chance you have of feeling it's effect. So if Wavelength = Velocity(speed of sound ft/sec) divided by Frequency(Hz.per sec), a 100Hz Bass note is over 11 feet long.

In your case, allow the woofer to "breathe" by lifting the cabinet off the floor, and firing the subs into the floor at least 4-6" away, so that their output is "ducted" into the passenger compartment under the rear seat, using it as a port.

 

In this situation it is impossible to fire the subs upward or downward. The subs need to be mounted in a horrizontal position

 

Why cant they be fired upwards? I have mine going upwards, works great.

Forwards with port up is supposed to work well.

 

The subs will not fit behind the seats if fired upwards. Have about 6.5 inches to work with back there

 

Well, if you can't fit it vertically, what does it matter what advise we give you?? It sounds as though you have no choice but to run the sub facing the firewall, so work with what you've got. Facing the port up will work fine.

 

ok sorry maybe im not being clear. my two options are to have the cone of the sub facing the front of the vehicle(and having maybe 1 inch of clearance from the sub to the back of the seat), OR have the cone facing the rear of the vehicle and having an inch of clearance from the cone to the rear wall of the cab of the truck.

 

The result of putting a subwoofer 1 inch away from a barrier is poor sound, and invariably a blown woofer. As example, put your hand a centimeter away from your mouth and yell, and then try it without the hand.
I take it that you are stuck with 10" woofers? Too much for the airspace you are trying to fill, in the cab of a truck in my opinion. I'd suggest 2or4 - 8" instead of 10". This will allow you the space and better cabinet design, plus 2-8's have more cone surface area than 1-10".

Making the baffle of the driver on a slant ( \ ), will give you more mounting area, and allow the driver to fire under the seat. Take a look at simple Transmission Line cabinets.Acoustic transmission line - Wikipedia, the free encyclopedia here.

 

There is definetly not enough room for a line transmission box. Sealed or a small vented box is the only option. I do like the idea of 2 8" drivers, but that is if the sub hasn't been bought yet... I can see a potential issue with box volume with 2 8" tho... I think a single 10 in a sealed box or an 8 in a decently sized vented box is the only real options here. OP, have you looked into "stealth" boxes for your truck? yeah, they aren't SPL level, but seriously, this most definetly isnt an SPL build, am I right? I'm thinking you're looking for as much output as you can muster with the space you have. A decent 8" in a ported box sounds like a winner to me. Otherwise, I'd say to run a sealed 10. We could argue all day on what is an optimal setup, but in your situation, you have to work with what you have.

 

ive done a few of those even with a pair of 10's... subs firing forward and a port or ports firing to the sides... works excellent... should be able to get arounf 2.2 cubic feet in there total... I used the kenwood low profile subs and 2 3" round aero ports ( i believe they were 16 or 18" long ) ... one per side per sub... box was partitioned in the middle for strength
narrow on top and wide at bottom... just make sure to leave 4-6" from sides to allow port to breathe