Why not horns?

"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.

I have a question for the horn guys.

A complex musical signal has both compression and rarification components of it's pressure wave. I can see how the compression component interacts with the horn.
How does the rarification component react with it, if at all?

Thanks!

Mapman, the original Walsh Drivers had 2 such mechanical cross-overs. I suspect that there was some cross-over in the lower than the extreme upper frequencies as well. The DDD doesn't have any such mechanical cross-overs.

"Mapman, the original Walsh Drivers had 2 such mechanical cross-overs. I suspect that there was some cross-over in the lower than the extreme upper frequencies as well."

That is correct the original OHM Walsh drivers used three distinct sections for low, mid, and high end that resulted in two physical equivalents of a "crossover" between sections, though I would not equate these "physical crossovers" to electronic ones in regards to how they behave, particularly in regards to coherence.

"The DDD doesn't have any such mechanical cross-overs"

That is correct also, though an external electronic crossover and non walsh bass driver is used for full range in most GPs.

In the case of the OHM CLS, the Walsh driver, crossover, and tweeter are all considered part of the full range "CLS" driver.

In either GP or OHM case, for full range, with exception of the GP Unicorn, two drivers and a crossover are used.

Prez-
Here is an anonymous contribution sent to me by a horn enthusiast. I hope it provides some clarification.

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I am not an expert on this but, when the sound forms in a pipe, and it leaves the end or "mouth, it becomes mainly a refraction wave. At the throat it is a pressure wave

Due to an 180 degree phase shift , there is an abrupt drop in pressure at the end of the tube, and the wave is reflected back down the horn, and the cycle repeats itself.

But, if the tube is made into a horn shape the pressure drop is not nearly as intense at the mouth, and the refraction wave is diminished so only a small portion of it reflects back down the horn. The throat of the horn is a High pressure wave.

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More from the same source:

from.....http://www.physicsclassroom.com/class/sound/u11l3d.cfm

Refraction of Sound Waves

Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the medium (and its properties) are changed, the speed of the waves are changed. Thus, waves passing from one medium to another will undergo refraction.