Well, it's here. First impression out of the box: IT'S BIG!! It's a really nice looking sub, real solid. The UPS guy used a "climber" to bring it upstairs. First, I just want to say how impressed I am with my towers that I created about 6 months ago. I never really appreciated how deep and low, and musical they are until I sold my Velodyne sub, and went "subless" in just stereo. Man, I love my towers! They have twin Vifa 8" drivers, the same ones used in Mackey studio monitors, cast magnesium baskets, mineral filled cones, coupled with 1" Vifa silk domes, and Audax midranges, I'm amazed when I listen to them, and yes, they too respond down to 20hz. Now, listening impressions of the PB10-ISD. I listened first to the towers by themselves in stereo, then the PB10. Played Darious Rucker "This Is My World", because it has nice and deep bass, good imaging, just a very clean song. After adjusting the sub level to a nice even level, it roughly ended up at half way on the dial, I compared the sub to the towers. It sounds great, it adds db's on the very lower octaves, and fills the room out really nice with bass. It would be easy to over adjust it to too high of a level, and it would overpower the music, you need to adjust to blend in just right, and it will be in the background and still let you hear all the fine details and imaging. After I set the levels, I play one more song, Eminem "Just loose it" and it really shined, it's a very musical sub, and it likes showing it's different tones, and the song has kind of a "boing" bass beat to it, and it reproduced it to a Tee, you certainly feel like your hearing exactly what they heard when they created and mixed the song. After the two songs, I did some measurements, the meat and potatoes, low bass sweeps with the sound meter. I can loop a audio segment over and over, so I did some full sweeps, then concentrated on the two lowest segments, the 25hz, and 20hz. First, I get a uneasy, scary feeling when I listen to 20hz, it just kind of freaks my nerves out even at low levels, if you haven't heard it before, it's a weird feeling. It must have something to do with a natural reaction, primordial earthquake sensing, I don't know Anyway, at the two lowest octaves, my towers drop about 3db's at 25hz and 6db's at 20hz. The PB10 is amazing, it does not drop at 20hz, it goes up 2db, and amazingly, it goes up further about 4.5db's at 20hz. Every sub I've ever tested has gone down at these last two octaves except for the PB10-ISD! And like I said, it's a really freaky feeling at 20hz, sounds like you need to turn it down because your brain thinks something is happening like a accident or something. I may be sensitive, I don't know Anyway, it's going to be fun watching a movie tonight, because I know that's where the real impact will happen, on music I may or may not run it depending on the material, there is something to be said for running stereo subs like in the towers, it sounds really good too.