OHm micro walsh series...

This is out of Ohm Walsh loudspeakers Technical White Paper dated 1981.
((The engineering of single wide-range drivers, such as the original Walsh loudspeaker driver, entails trading off efficiency for bandwidth. Perhaps the single most important compromise is the voice-coil mass decison. A coil, large and heavy enough to provide efficient bass responce, will not provide adequate high-frequency range. Conversely, a low-mass coil with excellent high-frequency performance will not be able to generate large low-frequency excursions. So, while the OHM F is the ultimate embodiment of Walsh technology, it requires substantial power to achieve loud sound pressure levels. Also, while the 360-degree dispersion of the Ohm F produces remarkable stereo imaging., it requires rather careful placement in the listening-room. The Ohm Walsh Loudspeakers utilize unconventional technology to provide a less expensive speaker which is substantially more efficient and less critical of room placement, but still coherent over a wide listening area.))
They are NOT omni, so it must be the coherent sound over a wide listening area is why I like them.
We took our drapes down and replaced then with verticals and also took down 64 sq' of old SONEX that was falling-apart and now the room is too lively for my taste; I have to do something about that.

The use of the word "coherent" in this specific sentence may not be the most appropriate word for what they are trying to describe: "The Ohm Walsh Loudspeakers utilize unconventional technology to provide a less expensive speaker which is substantially more efficient and less critical of room placement, but still coherent over a wide listening area. By that, what i'm trying to say is the sound produced by such a design is NOT coherent so much as it is "equally diffuse".

While some may wonder how the sound radiating out of the rear of a mid-woofer combined with a forward firing tweeter could be "equally diffuse", that is simple. All of the sound that one hears is "leaked" through all of the holes in the metal canister and the material that lines the inside of that "cage". As such, the "beaminess" of the tweeter at higher frequencies is nullified due to all of the diffraction / internal reflections taking place. The end result is that one hears the sound eminating through the holes in the canister, not from any single driver. There is no direct radiation, hence everything is "equally diffuse", which is the opposite of providing a point source of radiation that exhibits a "coherent" wave-front. Sean
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Some years back, i took the cans off a pair of 4XO's and i could not hear a differance when i slipped then off and on again; i did this several times. There must have been a differance, but my ears could not hear it. You know...they used to think the bumblebee could not fly.

You have to search their site to see the current ones are not omnis, as this thread indicates. They physically damp the rear radiation from the Walsh driver in all the main models, and use a conventional tweeter starting around 8 or 10k. These tweeters are seriously toed in by default.

If you talk to them they specifically disavow omni-directional radiation.

Ok well, the Micros were originally omni up to a little past 1 Khz, I was working at Ohm for a while and I began designing the Micros while John (the president and main resident speaker designer) was away on vacation. After returning from his vacation he was surprised and pleased with the results from the initial prototypes so we set about completing the design in earnest, working together. I guess they've made some changes to reduce the omni ratiation pattern to lower frequencies. Once you get to a low enough frequency, they are of course, still omnidirectional.
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Critofur (Christopher)