Why not horns?

Yes horns and omni drivers are a unique combo for sure.

Most GP designs appear to limit the coverage of the DDD driver to the upper frequencies where Walsh drivers operate in a mostly wave bending manner, as I understand it. This is supplemented by more traditional dynamic drivers for the low end.

The Unicorn apparently trys to extend the range of the DDD lower where it like all Walshes I believe operate more pistonically in producing bass, but that does not appear to be the strength of the DDD. The horn loading and equalization applied in the Unicorn to the DDD bass region output appears to compensate for that.

Macrojack, my 4.5" drivers are only good to 70-75dB because I run them full range from 45-15,000hz. If they were cut at 300hz like your horns, they could be played over 100dB.

If you go with Folded transmission line or Standard transmission line they advertise that you can get the bass and volume levels.

I believe this Tang-Band W4-1337SD will give similar performance to your horns. I have used it in a cabinet as small as 8 1/2" high. You will loose some bass as compared to a larger cabinet but if you put them against the wall, you should be okay. I found the HF ttshhh ttshh, annoying and would require a low-pass filter to cut or reduce the HF. I also prefer the snappy, softer sound of paper to the crystalline clarity of titanium. But I also use bi-polar solid state amplification and CD's.

There are many good single drivers (so I am told). Especially the PHY and Supravox if you are willing to spend the money. Also Jordan JX-92S but I found them to be thin in the bass. Even with a large transmission line cabinet.

Hope this clarifies things for you.

Mapman, the DDD appears to be full range till it reaches well into the bass region. After that the DDD driver would need to be augmented with a woofer/sub-woofer for full range classification. Those lower frequencies have less apparent directional ques, and probably maintain the illusion of omni directional presentation well. Keeping the cross-over away from alternate drivers at higher frequencies where our ears are most sensitive and usually are have the narrowest directivity would seem to be preferable. Again the DDD doesn't have the mechanical cross-overs that the original Walsh driver had. Of course the catch is; they're pretty darn expensive.

Yes horns and omni drivers are a unique combo for sure.

I've heard an omni-horn system. Sits on top of the local firehouse. Very clear, loud sound, but only one frequency. THAT gets boring in a hurry =;)

"Again the DDD doesn't have the mechanical cross-overs that the original Walsh driver had. Of course the catch is; they're pretty darn expensive."

no, but with teh exception of the Unicorn, it is not full range and supplemental drivers with electronic crossover are used.

I suspect the "mechanical crossover" of the original Walsh behaves better from a coherency perspective in that crossovers tend to work against coherency in general it seems.

DDD covers higher and mid frequencies and crosses over toward the low end of the audio spectrum. OHM CLS covers lower and mid frequencies and crosses over higher (about 10khz I believe). Most, particularly as they age into their 40s or so, cannot hear above 14 khz or so, so that is the argument for the CLS approach.

All Walsh drivers operate via wave bending at higher frequencies and transition gradually to more pistonic motion to produce lower frequencies. That would indicate DDD produces more frequencies using wave bending than OHM and OHM more using pistonic motion to cover bass, however my understanding is that both apply the Walsh driver principle however differently in these ways. That is how it has been explained to me.

So we all can chose our preferred designs and sounds. OHMs in general will cost a lot less than GP however, that much seems certain.