Gday all I am running two FI Q 12" D2's in a daily driver with a box that was built for it by a local car audio installer

using a single round port. Sounds reasonable but no where near as loud as I expected from these speakers. I am driving them with a Hifonics 2k rms amp Boot mounted Optima inline with another optima under the hood. Also have a 2.5 Frd Cap. This is a boot mount install in a Aussie car

Called a XR6 Family sized four door sedan.. ATM I have the speakers behind the back seat pointing into the car and the port facing the same way. Metered this setup at 132.5 before i upgraded the batteries seen alot better scores out of single speaker setups with similar sized cars..

Was looking at getting a Decent box constructed by a Local installer am looking at a Slot port box or even Sealed Always had Ported boxes

guess I am scared of going to Sealed and losing even more volume that it has now IE 128 or lower DB.. I know we all say I wanted SQ more than SPL numbers but in truth I probably should have gone BTL and not Q but at the time thought the BTL's were only good for single tones IE bass racing guess we all learn something .. So the installer knows he needs 2.5 Cub foot per speaker and 12-16 square inches of vent area per cubic foot of volume, but he isnt sure of Slot port opening sizes IE 3" or 4" Any Help or insight into this lol...

Thought things like this would be easy to work out IE 4.5 - 5Cubic foot of air needed for the speakers and say roughly 30 Inches of Slot port would

be calculated by Opening size Vrs Length of the port to get the right amount of Inches needed by the port.. Maybe I am missing something.

Thanks in advance to any help

Trevor

Edited May 1, 200916 yr by Snafu

The BTL's are by no means SPL only subs. I'm not sure I understand your question about the port area though.

ok Just rang the installer here is his Question Verbatim lol I am no box or speaker expert and will never claim to be hence why I am

trying to find someone else to build the box for me and hitting dead ends lol ..

I always thought programs like Bass Box pro would work this out ..

lol

Anyways the Question is for two 12"q's Going slot port Tuned to 32 Hertz.

Need to know the exact port dimesions Eg port opening length, Width and Size..

Again don't shoot the Messenger lol I am only passing on his question ...

Thanks for the quick response ..

Trev

A general rule of thumb is 12-16 sq. in. of port area per cubic foot.

What is the maximum size the box can be and I will make a design he can build from.

Brian

Thanks mate I will give you a link later today with my exact Trunk measurements including a diagram ...

Thanks muchly ...Anything I can do to repay you for this I will .. I do custom Laser Engraving so who knows maybe I can

pay you back with some custom laser engraved plates for your ride..

Trevor