Never owned the 8b's, but I have had the 9's here for several years with no intent to upgrade. Even at 90dB, the 9's are 4 ohm speakers (with a dip to 3.2) so they need some juice to sound their best. I would suggest a minimum of 100wpc @ 4ohms tube amps, or 200 wpc @ 8ohms SS. They sounded very nice with 100wpc (@ 4ohms) hybrid Lamm M1.1's (which are known to sound more powerful than their rating), and they sound even better with my current Clayton Class A monoblocks which put out 200wpc @ 8ohms and 400wpc @ 4ohms. The Clayton's control the bass better than the Lamm's did, which may be a function of the amp's sonic signature, as well as the extra power. I have also successfully used a McCormack DNA500 and Cary MB500 monoblocks, which are both 500wpc @ 8ohms. I liked the sound of the Cary amps slightly better than the McCormack, because the Cary's have a nice juicy quality in the midrange, and better high frequencies IMO than the McCormack. However, the Cary's were a bit noisier than the McCormack which is why I ultimately sold them. In my experience, the 9's pass along pretty much what you feed them. The midrange and treble are very clear and grainless and there is plenty of bass, which is pretty well defined due to the 4, 7-inch drivers. According to Aerial, the 9's are said to be a combination HT/music speaker, and an upgrade to the 10T, and IMO they succeed. They are built to Aerial's exacting standards, use improved drivers compared to previous models, and IMO are right there with simlar priced competition. In the past two years, I have used them solely for music playback (although I previously used them in a music/HT setup) and I would probably only sell them if I were able to afford something much more expensive (like 20T's) or if I wanted more efficient speakers so I could use moderately powered tube amps. The 9's are fairly easy to position with the front firing drivers and down firing port, but they do need some air around them so they don't sound boomy on some material. If your room is smaller, you will need good bass control (bass traps, etc.) and also to keep them away from the wall. My room is relatively large with 9-foot ceilings and, driven by a well damped amplifier, the bass is generally very nice, although occasionally displays some extra boom or excites the room a bit. In summary, the 9's are musical, dynamic speakers that are fun to listen to. They work well with all music and will reward better electronics with better sound. However, if your room is small, I would recommend considering the smaller Aerial LR5 with their SW12 sub (or two), which will require just as much amplifier power but which will provide better bass in a smaller room.
