I have a 10" JL audio w6 the old version 1 subwoofer, and I was needing to know how big I should build the box for a single cab chevy s-10. I want the most spl I can get with the room I got. Vented? Sealed? Cubic inches?
Go with JL’s box specs:
http://mobile.jlaudio.com/pdfs/8-12W6_BDS.pdf
for high SPL go with a ported box

Use what JL recommends.
Ported = accurate bass
sealed = exaggerated bass
More info here htpp://spkrbox1.spaces.live.com
References :
A.A.S. degree in Electronics/Industrial Electronics with 25 years in the mobile audio/consumer electronics field
As for size, you’ll only be able to build what will fit in your truck… JL’s sound killer in a ported box, but the drawback is ported boxes need to be a good size. Sounds like you’re going to have to make some sacrifices… Cab space, SPL, etc.
References :
Go with JL’s box specs:
http://mobile.jlaudio.com/pdfs/8-12W6_BDS.pdf
for high SPL go with a ported box
References :