Very interesting discussion. In the past month, my first experience integrating a sub-woofer into my system had some unexpected results. My Edgar Seismic Sub arrived about a month ago, before the Edgarhorn speakers. The Seismic is a 6' tall folded horn driven by a 18" JBL 2440. While waiting for the Edgarhorns, I practiced integrating the sub with my Alon Circes, which are rated flat ~ 20 Hz. Rather than bass reinforcement, the most noticable difference with the sub and Alons was improvement in sense of accoustic space. There were more cues to the physical size of the recording. For example, it was clearer to sense an intimate jazz venue from a symphony hall from a recording studio. The next difference was improvement in the clarity of mid and high frequencies. On the other hand, it was alot of work finding proper balance between sub bass level and overlap with the Circe, especially since there was no low-pass option on the dedicated sub x-over to roll-off the Circe's output level. I ended up using the lowest crossover setting of 30 Hz, and fairly low level. Now, with the Circes replaced by the Edgarhorns, it is completely different. The horns roll off at 80 Hz, and I'm still trying to find the proper x-over point and level and placement. Placement is limited due to the physical size of the horn sub. It is almost, but not all the way, into a corner. Also, the x-over point is much higher and more audible, ~ 70 Hz. The slope is 24 dB/octave, so I may need to go still lower. And still working on level matching, especially since Bruce recommends up to 6dB boost ~ 30Hz. So many variables to lock down. As for proper stereo reproduction, I am not prepared to commit to a second Seismic Sub, since my room size is only 15' x 18'. Anyway, my experience taught me that the benefit of the sub is NOT so much bass reinforcement, as spatial and clarity up higher. Thanks for a good thread.