I know it will have to be big but here's what I want..something that operates primarily between 10 and 25Hz to pick up the lowest pipes, some recordings have 64ft pipes lower than 16Hz(!) as well as the massive and airy decay of really large recording spaces. I don't want something that is gasping for it's last breath at 16Hz only to produce 90db or less with 25% distorion or more. I would prefer to use smaller drivers (10 or 12 even if it involves multiples). I find them to be more transparent, but in a big cabinet. I just have yet to find a 15 or 18 inch woofer that doesn't have an obvious sound. The question is what size box and or loading scheme would you suggest? I don't need the sub to have impact at 40-80 hertz, again it wold only be used under large speakers. I also need a good amp and crossover, something that can roll the sub out down low to keep it below 20 or 25. I realize this is different than most people want. Any ideas?