The physics of conventional enclosures shapes and sealed or bass-reflex speakers are inherently flawed. Power response varies too much with frequency for natural response. While well-braced 3/4"+ MDF or void-free plywood contain the back-wave of a driver it comes right through a thin driver cone. Ported bass/sub-bass enclosures also suffer from stored energy.
While conventional designs can compare well to each other they can't stand up to a live performance.
Implementation problems also cripple most speakers. Passive cross-overs mean the speaker can be no more sensitive than their dome tweeter so dynamic range is limited. Acoustically large enclosures in the tweeters' pass-band make diffraction a problem which is exacerbated by 90 degree enclosure edges.
The common theme below is uniform polar response, control of driver back waves, control of diffraction, and high dynamic range through active cross-overs (a 40W tweeter amp and 60W mid-bass amp on a 2-way equal a 200W amp with a passive XO) and/or high sensitivity (compression driver + waveguide, multiple woofers with mutual loading and half-space operation, etc.)
Getting away from that, you can use the actively quad-amplified = Orion++. Apart from the frequency range where the mid-range magnet and basket structure cause a more cardioid response it should be an acoustically small dipole through the fundamental frequency range of voice and instruments, with reduced side-wall + ceiling reflections (close to the perception threshold for image shift with a couple feet to the sidewalls) and 4.8dB (3X) better directivity than a conventional speaker providing clarity farther into the room. The driver back-wave is used to provide uniform polar response, and with proper placement (4' off theback-wall) back-wave reflections are delayed enough that they don't get confused with the direct sound. Woofer sensitivity approaches 100dB/2.83V. Wonderful natural sound and the most natural bass I've heard from any speaker in any room (mine was 13x19x8 which is a bit small).
I haven't heard them but the actively quad-amplified B&W snail-shaped nautilus should be very interesting. The baffles are acoustically small so it sould approximate a monopole at all frequencies. Damped transmission lines absorb the driver back-waves so they can't be re-reflected through the drivers. Tubular (including conical and curved)enclosures can be as stiff as 4" concrete.
The actively bi-amplified Linkwitz Pluto also uses acoustically small baffles on the ends of damped transmission lines (Only 1% of the midrange backwave reflections reach the driver cone) for very good results. Finishing my Pluto+ woofers to fill in the bottom end and applying the high-frequency shelving high-pass should produce world-class speakers. The omni-directional radiation pattern gives up clarity and imaging precision to the Orions at the same listening distance although they can be listened to at a much wider angle (closer distance) without loosing the phantom center so this is a placement issue. Imaging depth is less. Driver quality may be responsible for the last bit of the Orions' resolution which is absent in Pluto, but what do you expect for a $700 parts cost? Surprisingly close to the Orions but missing the last 1.5 octaves and some output capability; Pluto+ should fix that.
I haven't heard them but the Gedlee Magnum cum Laude should be very interesting. Uniform directivity is provided by a wave guide on the high end. Earl Geddes has a patented solution to horn diffraction problems. Uniform polar response is maintained as the horn transitions to the 15" bass driver due to the drivers' beaming. The large radius curves on the enclosure edges limit diffraction amplitude, and wide baffles push it out in the time domain.
If any one in the Seattle area has a set of those speakers I haven't listened to, I'd love to compare with the Plutos and Orions (currently in my workshop and not setup but that could be fixed).
