I visited HArper audio today, the vintage /custom speaker store in Broken Arrow.
Tom Harper is a very knowledgeable and nice guy, who has built a set of different speakers. I listened to a pair of bookshelfs: HH3 Full Range. these have a 6.5 inch woofer and a dome tweeter, crossover at about 2200 Hz (second order). THey had very impressive frequency range (into the 30's), and I could see the woofer doing a lot of work. Still, the sound was quite clean, and the frequency extension was very impressive. The proce on these is $250, which is a really good deal. Their efficiency is 89 db. I also listened to his obelisks: these are 3 ways, a dome tweeter, a dome mid, and a 10 inch woofer. The port is on the top of the pyramid, which is cool. Tom calls it a "venturi" cabinet, becuase the air out of the port accelerates. He says it leads to lower IM distortion, since this reduces the back pressure on the woofer. Certainly the bass ewas fine on this, down to the high 20's. The eff on these is 90-91 db. I thought they were nice sounding overall. Great for rock and roll music, home theater, etc.
Tom sells a high efficiency book shelf (HA 3db) which I could not hear, but look forward to hearing.
Tom is invited to the next GPAC meet, and maybe he'll bring a pair of obelisks there too.
-akhilesh