You want uniform dispersion up to a few kilohertz with a gradual reduction in total power response at the high end.
While "omni" speakers are one way to achieve that, designs with controlled directivity (dipoles, wave guides) accomplish the same end-goal with fewer interactions with nearby surfaces and a preservation of detail and "correctness" farther into the room.
Planar speakers don't qualify as dipoles. While they have sound coming off the front and back-sides, they're acoustically large at high frequencies so they suffer lobing problems instead of having an acoustic dipole's nice off-axis behavior (off-axis response is -3dB down from on-axis at 45 degrees, -6dB at 60 degrees, and non-existant by the time you move out to 90 degrees).
I've built pairs of Linkwitz Orions (open baffle) and Plutos (they don't really start getting directive until 2-3KHz. and have no baffle outside the 2" mid-tweeter). The Orions have more reach into the room.
Some time I'll get around to trying a wave guide without the problems that go with horns - Earl Geddes work looks real interesting.
While "omni" speakers are one way to achieve that, designs with controlled directivity (dipoles, wave guides) accomplish the same end-goal with fewer interactions with nearby surfaces and a preservation of detail and "correctness" farther into the room.
Planar speakers don't qualify as dipoles. While they have sound coming off the front and back-sides, they're acoustically large at high frequencies so they suffer lobing problems instead of having an acoustic dipole's nice off-axis behavior (off-axis response is -3dB down from on-axis at 45 degrees, -6dB at 60 degrees, and non-existant by the time you move out to 90 degrees).
I've built pairs of Linkwitz Orions (open baffle) and Plutos (they don't really start getting directive until 2-3KHz. and have no baffle outside the 2" mid-tweeter). The Orions have more reach into the room.
Some time I'll get around to trying a wave guide without the problems that go with horns - Earl Geddes work looks real interesting.