Was this ever produced?

[OrthoFan]

Double horn/Double tonearm/Double diaphragms -- https://ia801702.us.archive.org/BookRea ... 4&rotate=0 (Click image to make full size.)

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(Horn & Tonearm)

I've searched Google's patent database, off and on, for several weeks and can't find anything issued to the company or the inventor mentioned in the article.

I can understand the concept of the double horn -- one for bass, one for treble -- but don't see why a conventional tonearm and sound box, with a diaphragm sensitive to all frequencies, wouldn't work just as well.

OF

[CarlosV]

I can understand the concept of the double horn -- one for bass, one for treble -- but don't see why a conventional tonearm and sound box, with a diaphragm sensitive to all frequencies, wouldn't work just as well.

OF

There is an English design called Duophone, with two diaphragms in tandem linked to a single V-shaped needle arm, one diaphragm slightly larger than other, with the same advertised purpose of the smaller one reproducing trebles and the larger the basses. These soundboxes were made with mica diphragms, which in itself severely limited the response, so there is no real advantage in such design.

[OrthoFan]

Hi Carlos:

Many thanks for your reply.

I'm familiar with the Duophone, which used two sound boxes hooked to a single needle bar. They were positioned one in front of the other. From what I can tell, the RI Watkins Co's tonearm used two diaphragms facing each other, encased in a single sound box, driving a single needle, with the sound emitted through separate conduits throughout the horn.

I actually saw a tonearm/sound box assembly very close in appearance to the one in the article, but the patent date was 1922, or six years earlier than the article. (Unfortunately, I can't find it now.) Because of it's date, I initially assumed the patent was for a different tonearm altogether. Today, on re-reading the article, I noticed it states, "the machine is fully covered by patents which are OWNED by Paul O Richmond..."--owned, as opposed to "invented by." This leads me to suspect that Richmond may have simply purchased the right to use this style of tonearm and sound box assembly; possibly the horn as well, though so far, I've come across nothing like it in the patents. From the illustration, the horn looks gigantic, but the article states that it fits into a 17x17x16-inch space, which means it could have been easily used in a smaller or mid-size cabinet.

I realize that there's probably not much interest in these quasi-scientific designs, but I find some of them fascinating, and wonder what they would have sounded like.

OF

[Marco Gilardetti]

I can understand the concept of the double horn -- one for bass, one for treble -- but don't see why a conventional tonearm and sound box, with a diaphragm sensitive to all frequencies, wouldn't work just as well.

It has to be considered that throughout the acoustic gramophones era, the physics/mathemathics of horn loading was mostly yet to be discovered and partly misunderstood. The preminent theory back then was that a horn acted as a "concentrator/conveyor of sound", while today we know that it acts primarily as an acoustic impedance adapter. Horns' engineering was then mostly a trial-and-error process, and, before the orthophonic era, countless examples of gramophones with absolutely ill-designed horns were mass produced (even by renowned makes like Victor).

Also, we, as humans, are naturally accustomed to the audible sounds' frequency range (usually considered to be 20 Hz to 20 KHz), so we consider it to be a "normal thing", nothing extraordinary. But from a physical standpoint, this range is instead very wide as it spans over 3 orders of magnitude. Even with today technology it's not easy to produce a transducer that can deal with this entire range, so most loudspeaker systems are multi-way (woofer + tweeter or woofer + midrange + tweeter) and have built-in frequency dividing crossovers. In critical cases, bi-amplification or bi-wiring is used.

So, overall, the idea of having a diaphragm + horn assembly optimized for lower frequencies and a diaphragm + horn optimized for mid/high frequencies is not a bad one. If you look at highly regarded horn-loaded speakers, like the Klipschorn just to name one, they're made exactly that way. The above pictured "double-horn" in some way predates the idea of concentric speakers, like the Jensen G-600 Triaxial, again just to name one.

My concern about it is that, with gramophones, all horns (whichever brand and make) were already "optimized" - to the best of each makes' knowledge and ability - to have a good (decent) bass response, which however turned out to be insufficient in all cases. No gramophone has a linear frequency response, and all of them blast too much in the mid/high end of the spectrum; there is no such thing as a gramophone with "too much bass". So I can hardly figure that adding a mid-high optimised horn would improve the sound significantly. I actually think that it could even emphasize the typical unbalanced sound of the gramophone.

In any case, beaing a physicist, I am in turn always fascinated by these "pseudo-scientific", as you said, gimmicks that show the ingenuity of many people that made the history of sound reproduction. Thanks for sharing this image!

[Panatropia]

I can understand the concept of the double horn -- one for bass, one for treble -- but don't see why a conventional tonearm and sound box, with a diaphragm sensitive to all frequencies, wouldn't work just as well.

It has to be considered that throughout the acoustic gramophones era, the physics/mathemathics of horn loading was mostly yet to be discovered and partly misunderstood. The preminent theory back then was that a horn acted as a "concentrator/conveyor of sound", while today we know that it acts primarily as an acoustic impedance adapter. Horns' engineering was then mostly a trial-and-error process, and, before the orthophonic era, countless examples of gramophones with absolutely ill-designed horns were mass produced (even by renowned makes like Victor).

Also, we, as humans, are naturally accustomed to the audible sounds' frequency range (usually considered to be 20 Hz to 20 KHz), so we consider it to be a "normal thing", nothing extraordinary. But from a physical standpoint, this range is instead very wide as it spans over 3 orders of magnitude. Even with today technology it's not easy to produce a transducer that can deal with this entire range, so most loudspeaker systems are multi-way (woofer + tweeter or woofer + midrange + tweeter) and have built-in frequency dividing crossovers. In critical cases, bi-amplification or bi-wiring is used.

So, overall, the idea of having a diaphragm + horn assembly optimized for lower frequencies and a diaphragm + horn optimized for mid/high frequencies is not a bad one. If you look at highly regarded horn-loaded speakers, like the Klipschorn just to name one, they're made exactly that way. The above pictured "double-horn" in some way predates the idea of concentric speakers, like the Jensen G-600 Triaxial, again just to name one.

My concern about it is that, with gramophones, all horns (whichever brand and make) were already "optimized" - to the best of each makes' knowledge and ability - to have a good (decent) bass response, which however turned out to be insufficient in all cases. No gramophone has a linear frequency response, and all of them blast too much in the mid/high end of the spectrum; there is no such thing as a gramophone with "too much bass". So I can hardly figure that adding a mid-high optimised horn would improve the sound significantly. I actually think that it could even emphasize the typical unbalanced sound of the gramophone.

In any case, beaing a physicist, I am in turn always fascinated by these "pseudo-scientific", as you said, gimmicks that show the ingenuity of many people that made the history of sound reproduction. Thanks for sharing this image!

Indeed Marco. And here is another fellow who would doubtless concur.

[Marco Gilardetti]

Wow, what an outstanding setup! So irrational that I have to love it!

[Panatropia]

Addendum....

[Marco Gilardetti]

A little bit more rational. Just a bit.

[startgroove]

Decades ago, I examined a large cabinet phonograph which had two different size horns in it. It appeared to be a prototype, or maybe home made. It had a single, large aluminum diaphragm reproducer which, on one side of the diaphragm had a "restrictor" opening which appeared to block vibrations from the center of the diaphragm, and on the other side of the diaphragm, another opening which appeared to block vibrations from the outer edge of the diaphragm. Each side of the diaphragm loaded a double tubed tone-arm which were then connected to one long horn with a large opening and one shorter horn. Both horns were enclosed inside the cabinet, but their openings exited through grilles, each one on opposite sides of the turntable. I've since lost the contact, and have no idea what happened to that machine.

Meanwhile, I set up this Victor II with a large horn and an "Add A Tone" reproducer. It's not the same as the machine described above, but it does have some unusual sound characteristics. For one thing, when I listen standing back from the machine a few feet, the sound seems tonally fuller than an Exhibition reproducer loading the standard size Victor II horn. An early electric recording sounds particularly good to me on this set up. Secondly, if I place my head in a position between the large horn shown and the small horn on the reproducer, (making position adjustments to equalize volume), I believe my ears detected a significant difference in phasing and tone.

I'm guessing the research into this kind of expanded range playback came right at the time that electrically controlled equalization became practical, and therefore never went much further in development (at least not for mass production).