High efficient speakers

This should not even be a discussion.....KLIPSCH hands down!

I have a 15 wpc push pull Shindo amp and I'm finding that my Devore Super 8s don't have enough bottom end for me. The Devores are special speakers, with wonderful tonality and coherence in the mids and highs, but they just don't have the deep slam that I crave. I suspect that you're finding the same with your AN J's. The fellow that sold me the Super 8s moved up to the 9s and he reports that he's very pleased with them. When I took my amp to my friends with HE speakers Cain & Cain Abbys (95 dB) and Klipsch LaScalas (105 dB) my amp sounded absolutely wonderful. Conclusion- my amp needs a HE speaker for it to really shine.

some of the best speakers I ever heard were at AK Fest in Detroit MI. They were homemade with 2 Fostex drivers ($68 each driver) and a supertweeter, the palpability was breathtaking. They were not full range (there is always a catch) being bass deficient but were easily the best sound at the show even though there was a lot of high end rooms including Audio Note with $13,000.00 E silver speakers and level 6 pre and conquest power.

I'm a big fan of the vintage Klipsch (Khorns and LaScalas - have owned 2 pairs of LaScalas both of which I modified). They are hard to beat as a pairing with low-powered SET amps, but definitely can be improved upon in many ways, especially the tweets. A few years ago moved out of my large workspace and started to condense my two systems into one. I use 9 watt 300B SET's also. I live in a small renovated tudor house. The room I listen in is similar in scale, but just a bit smaller than yours. I could not make the Klipsch speakers work in my space and my wife hated their size and appearance, and they were simply too large and overwhelming for the size of room I'm in (about 12X25, ceiling slopes from 8-12 feet - forced to setup on the long wall). So I searched for three years for a speaker that could satisfy me. I was spoiled by the speed and imaging of those horns in my studio. It is an excellent way to go, but can overwhelm a small space (yours is not as small as mine). I tried many different speakers and even different amps a few times. Of the speakers I did not like Zu Druids. Silverline Sonatina's were damn good, but didn't reach low enough. SR17's are great but not with SET. Galante Rhapsodys (or the larger version - I think Buckingham perhaps) worked very well, but are no longer made and don't know if driver replacements are available. Again, lows were lacking. Long story short; I've ended up settling on Coincident Super Eclipse III's and am delighted with those speakers. Lightening fast. Outstanding soundstage. Reach down real low (though I'd say on the MOST demanding of bass passages they DO show they could use just a bit more power - it is very rare, but it does occur in perhaps 1/100 recordings I enjoy). Anyway, I'd recommend them highly.

Good luck!

Since your space is tight, a medium sized Klipsch may work better. Cornwalls are much more compact than LaScalas or Khorns but still extremely efficient and won't mind the rear wall.