Probably a topic for a different thread, but I would be really interested in better understanding how the better known Walsh style driver/designs differ from the more conventional approach in terms of these common parameters that help determine speaker performance.
How does a downward oriented, open-back Walsh driver manage to deliver seemingly flat and extended frequency response at very high SPLs horizontally in a largely omnidirectional manner compared to a say a single similar sized conventional driver generally firing more directly at the listener?
The answer seems to lie somewhere in the domain of "wave bending" in the Walsh theory, as opposed to pistonic motion which I believe accounts for most of the output associated with traditional dynamic designs?
I kind of understand the theory based on wave propogation through materials of different density "bending" or diffracting the wave, but would have no clue how to relate it in technical terms comparable to what Drew and others here have so eloquently related, nor how to apply it effectively in practice, other than via trail and error perhaps.
Here's what Wikipedia has to say about it FWIW:
"Bending wave loudspeakers
Unbalanced scales.svg
The neutrality of this section is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (October 2010)
Bending wave transducers use a diaphragm that is intentionally flexible. The rigidity of the material increases from the center to the outside. Short wavelengths radiate primarily from the inner area, while longer waves reach the edge of the speaker. To prevent reflections from the outside back into the center, long waves are absorbed by a surrounding damper. Such transducers can cover a wide frequency range (80 Hz to 35,000 Hz) and have been promoted as being close to an ideal point sound source.[49] This uncommon approach is being taken by only a very few manufacturers, in very different arrangements.
The Ohm Walsh loudspeakers use a unique driver designed by Lincoln Walsh, who had been a radar development engineer in WWII. He became interested in audio equipment design and his last project was a unique, one-way speaker using a single driver. The cone faced down into a sealed, airtight enclosure. Rather than move back-and-forth as conventional speakers do, the cone rippled and created sound in a manner known in RF electronics as a "transmission line". The new speaker created a cylindrical sound field. Lincoln Walsh died before his speaker was released to the public. The Ohm Acoustics firm has produced several loudspeaker models using the Walsh driver design since then.
The German firm, Manger, has designed and produced a bending wave driver that at first glance appears conventional. In fact, the round panel attached to the voice coil bends in a carefully controlled way to produce full range sound.[50] Josef W. Manger was awarded with the "Diesel Medal" for extraordinary developments and inventions by the German institute of inventions."
How does a downward oriented, open-back Walsh driver manage to deliver seemingly flat and extended frequency response at very high SPLs horizontally in a largely omnidirectional manner compared to a say a single similar sized conventional driver generally firing more directly at the listener?
The answer seems to lie somewhere in the domain of "wave bending" in the Walsh theory, as opposed to pistonic motion which I believe accounts for most of the output associated with traditional dynamic designs?
I kind of understand the theory based on wave propogation through materials of different density "bending" or diffracting the wave, but would have no clue how to relate it in technical terms comparable to what Drew and others here have so eloquently related, nor how to apply it effectively in practice, other than via trail and error perhaps.
Here's what Wikipedia has to say about it FWIW:
"Bending wave loudspeakers
Unbalanced scales.svg
The neutrality of this section is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (October 2010)
Bending wave transducers use a diaphragm that is intentionally flexible. The rigidity of the material increases from the center to the outside. Short wavelengths radiate primarily from the inner area, while longer waves reach the edge of the speaker. To prevent reflections from the outside back into the center, long waves are absorbed by a surrounding damper. Such transducers can cover a wide frequency range (80 Hz to 35,000 Hz) and have been promoted as being close to an ideal point sound source.[49] This uncommon approach is being taken by only a very few manufacturers, in very different arrangements.
The Ohm Walsh loudspeakers use a unique driver designed by Lincoln Walsh, who had been a radar development engineer in WWII. He became interested in audio equipment design and his last project was a unique, one-way speaker using a single driver. The cone faced down into a sealed, airtight enclosure. Rather than move back-and-forth as conventional speakers do, the cone rippled and created sound in a manner known in RF electronics as a "transmission line". The new speaker created a cylindrical sound field. Lincoln Walsh died before his speaker was released to the public. The Ohm Acoustics firm has produced several loudspeaker models using the Walsh driver design since then.
The German firm, Manger, has designed and produced a bending wave driver that at first glance appears conventional. In fact, the round panel attached to the voice coil bends in a carefully controlled way to produce full range sound.[50] Josef W. Manger was awarded with the "Diesel Medal" for extraordinary developments and inventions by the German institute of inventions."