Hi all, I just finished my 4th & 5th subwoofers... thanks to all for your help! I guess I've come a long way since I got here. This forum is absolutely invaluable. Anyway... I wanted a couple of subs for my B&W DM602S3 speakers. They have nice bass, but are seriously lacking in the 50 hz and under area. I built a pair of sealed 130L subs, based on the Cerwin-Vega HED-12 driver (the only one I've been able to find around here at a decent price). I have previously used this driver on a 118L design, tuned to 20 Hz, and was surprised at the results (better than I couldhave ever expected). So, I thought about going sealed this time, just to see how much sound quality I could gain by doing so. Well, I learned a lot from the lesson. While the ported subs (I'm using them at my HT) go down very deep, and have lots of SPLs, the sealed subs are almost undetectable... that is, until I turn them off. Then, the B&W's sound positively anemic. It's amazing how needed a good pair of subs are for music listening. My best experience came with the "Kind of Blue" SACD, playing through my system (a modded BottleHead tube preamp and a Rotel RB1070 amp, plus the ubiquitous 300-794). The bass lines are perfectly defined now - no longer a soft, faint image of a bass, but a real, clear and fast sonic image. The lowest of the low bass is not as audible here, but to be honest, I can't think of any CD that really needs 20 Hz bass (except for pipe organs and Marcus Miller, that is). I wonder - how much could I gain by using a better subwoofer driver next time? Hmmm.... tempting! Even more tempting, though, is to build an IB now.