Thanks to everyone for their input. After adding the tube preamp (TAD-150) and getting some nice improvements, I finally got around to auditioning a Velodyne DD-10 sub in my room. The room is 14'x25' with vaulted ceilings. Since the best sub positions were at the complete opposite side of the room from the preamps/amp, I had to rig some long cables as well as bring a TV into the room. (It became clear to me that Velodyne designed this EQ stuff to be easily calibrated with a HT, not necessarily in a 2 channel setup). Anyway, it took a while to understand the nuances of the Velodyne EQ software, but at the end I was pretty impressed. With the Velo volume at 0, the Aeons had a nice flat response down to about 35 Hz, well below the 43 in the specs. With the Velo on and bass turned up to match the level of the speakers, there were a couple of room resonances at about 42 and 63 Hz that stood out. Moving the sub from a position about 3 ft. from the wall out to about 6 feet (still spouse-friendly positioning) gave a much flatter response, but didn't make the room resonances completely disappear. Using the EQ though, I was able to get it pretty flat from 25 Hz up, with some tailing off at 20 Hz and nothing lower. This profile was much better than the "flat" example they give in the manual. It was important to play with the crossover slope settings to achieve this. The phase and polarity were good to start with. Saved the settings and listened to some music. The velo definitely added something, but the superlatives that reviewers use to describe this sub did not come to mind. Just seemed to fill in the deep end nicely. (By the way, the crossover was set at 70 Hz). I was very impressed with the EQ part, but am thinking maybe a DD-12 would sound better. The DD-10 was working very hard at high volume levels. Anyway, I will demo a Depth next week sometime, but after thinking about this I don't think I should be in a hurry to make a decision. Some others have suggested multiple subs, e.g. a pair of ACI Force subs, or a pair of Onix ULW-10s. This might flatten out the room modes a bit without EQ and definitely push more air than a single 10" Velodyne. So many possibilities.
On an unrelated topic, the TAD-150 does not have any line level outputs, and I need to run my CD player to a second preamp for the whole house system. Would putting high quality Y-adapters such as
http://www.monstercable.com/productPage.asp?pin=655
on the CD player outputs degrade the signal?
Thanks for your help and advice.
Jon