Last weekend I finally finished my IB subwoofer so I thought I'd share pictures and results. Here's the pics I used 4 Ascendant Atlas 15 inch woofers and I'm powering it with a single PE 250 watt plate amplifier. This is an amplifier that I already had laying around at the house, so it made sense to give it a try before spending more money. So far it does a fine job, though it does get warm after some especially powerful scenes. MikeNg asks: "What's the impedance on each of those Atlas'? Can the amp take the ohm load you're giving it? It might be working too hard." The Atlas woofers can be wired a number of different ways with their unique DVC configuration. Right now they're wired Hi-Q (gold terminals open) which means they're 4 ohms/woofer. I wired them series/parallel. This gives a single 4 ohm load to the amplifier. I did lots of measuring and dialed in the BFD equalizer this weekend. I tried to apply only the minimal amount of EQ to get it flat to +/- 3dB. You can see the results in the last pic. Roll-off on the upper and lower ends is due to filters in the plate amp. I'm now using one extra filter to play with different house curves - presently -8dB @180Hz, BW=90/60. It sounds great. I had friends over last night to watch Batman Begins and we were all thoroughly impressed. Certainly more powerful than the SVS 25-31PC that it replaces. I now have more sub headroom than I'll ever need. Sound quality is very good, too. It doesn't seem like its a quantum leap beyond the SVS (as you might be led to believe) but its possible that my ears just aren't good enough or I haven't had enough time to really tell the difference.