I have two JL Audio 12" W4, and I have been using them in a 140 litre (or rather 2 x 70 litre, it had a seperating wall) ported box in myt 1995 Chevy Suburban, driven by a SoundStream Li'l Wonder amp. And it sounded very good, both on low and too high volume...

The problem is that I now have less room because I have put a Propane tank (LPG costs less than half as much as gasoline here in Norway) in the back, and I'm gonna build a rather strange measured box: 8 inch high, 48 inches long and 16 inches wide. According to JL Audio's recommendations that means that I can build either one dual sealed box split in half, like the old ported box, or I can build a ported box for one of the subs. I like tight bass, and it's important that it soulds good on low volume. So could you please give me your opinion on this? I'm leaning toward a sealed box, but then I'm not exactly an expert on these things...

Thanks in advance!