I need to build a new box for my SPL 15 due to getting a new vehicle (2005 Jeep Liberty). I'm thinking of going 3 cubic feet NET tuned to 38hz or so with 58 square inches of port area. Will this work out ok or do I need more air space? This will be a daily set up and likely won't be used to compete so I want something that is loud and decent sounding. Power wise I will be using a RF T30001bd @ 4ohm. I was previously using a 4.2 cubic foot box tuned to 32hz and it was quite good sounding but lacking in volume. I figured this time I would tune higher and try a smaller box to save some space.

Tuning higher will certainly net you increased output. If you can keep it as close to your original box size as possible that would be a plus. 36-38Hz would be just fine.

Best,

Mark

Going from 4.2 to 3 cubic feet = loss of efficiency = loss of output.....

Tuning a little higher might help...

Thanks for the input. I plan on sticking with 4.2 cubic feet and tuning to around 35hz. I'm hoping this gives me a decent sound. I have no idea on the acoustical response in a jeep liberty.

I'd say tune it to 40Hz.

I have a Memphis 15 PR in 4.3 cubes tuned to 40Hz with 112.5 sq inches of port area...with only 400 watts everyone thinks I'm pushing 1000 watts.

Thanks for all the input. I almost got all of the box together. I haven't cut the hole for the driver yet. I'm not too sure where to put it. Originally I had planned to have the sub on the top firing to the roof and the port on drivers side firing to rear. Looking at different SUV installs there are lots of sub and port firing to the back. I'm not sure which to go with.

I say toss a coin...

Ok I'll put it on the top of the box. That'll give me the opportunity to mount the sub inverted. One last question before I cut the hole. What is the cut out diameter for the SPL 15? Would 14" be big enough because thats the max my circle jig goes to? Thanks a lot!

I should update the site actually. I'll get the measurements for you tomorrow.

m

did anyone catch that. he is going to use 19.xx sq inches of port per cube. that could be your loss of input right there.

I should update the site actually. I'll get the measurements for you tomorrow.

m

Thanks. I think I managed to figured it out. I cut the hole 14 1/8" and it fit perfect. I saw that the SPL 12 required a 11 1/8" hole and the IXL 12 required a 11". The IXL 15 requires a 14" hole so I took at wild guess and used 14 1/8" for the SPL 15.

did anyone catch that. he is going to use 19.xx sq inches of port per cube. that could be your loss of input right there.

I'm using 57.75 square inches of port area. According to my calculations that is equal to 2.04 6 inch round ports. That should be plenty of port area for a 15" sub with 17mm excursion. At least I hope my logic is right. I really don't want to have to rebuild this box.

Well, I'm a day late.

The mounting diameter is................. what you said

You're welcome.