The ‘Mastersonic Organ’ John Goodell & Ellsworth Swedien, USA, 1949

The Mastersonic Organ was an improved tone wheel organ designed to produce more accurate pipe organ sounds. The designers,  John Goodell and Ellsworth Swedien, discovered that if they shaped the tone-wheel ‘pickups’ they could induce tones with different ‘natural’ harmonic content – rather than attempt to create a pure sine wave and artificially colour it as in the Hammond Organ. To achieve this the Mastersonic had individually shaped magnets for each tone wheel sound; a “string” magnet, a “flute” magnet, a “diapason” magnet, and so on.

Mastersonic Tone Generation

Mastersonic Tone Generation (Alan Conway Ashton ‘electronics, Music and Computers’ 1971)

“…There were twelve shafts with seven pitch wheels each which rotated near the irregularly shaped magnets wound with coils. Each of the pitch wheels contained twice as many rec­tangular teeth as the preceding one, so seven octaves were produced per shaft. Several differently shaped poles were dispersed radially around each wheel.”
Alan Conway Ashton electronics, Music and Computers

Each tone-wheel was shielded against magnetic interference from the other, adding to the bulk and complexity of the instrument. The instrument was controlled by a seven octave special keyboard, designed to simulate attack envelopes. The resulting sound was indeed a much more accurate pipe organ sound but at the expense of size; the Mastersonic was a huge, complex and expensive machine and few were built or sold.


‘Microsound’ Curtis Roads MIT 2001

ELECTRONICS, MUSIC AND COMPUTERS. Alan Conway Ashton. December 1971 UTEC-CSc-71-117

Robb Wave Organ. Morse Robb. Canada. 1927


The Robb Wave Organ designed by Morse Robb in Belleville, Ontario was said to be  musically superior to the Hammond Organ. The instrument attempted to reproduce the sound of a cathedral pipe organ by amplifying sounds generated by a similar tone-wheel mechanism. Prototype models were created in 1927 and the production model came on the market in 1936 and remained available until 1941.


A newspaper article on  the organ-printed almost ten years before it became available-was headlined: “Young Canadian Invents Pipeless Ethereal Organ” (Toronto Star, 1927). The Robb Wave Organ was more expensive than other electronic organs, and sales suffered because of the Depression and World War II. With only thirteen units sold, the company ceased operation in 1941. The Museum has preserved prototype and final tone wheels and drums from Mr Robb’s workshop.

Michael J. Murphy professor RTA School of Media talks about the Robb Wave Organ



Canada Science and Technology Museum

The ‘Choralcelo’ Melvin Severy & George.B. Sinclair. USA, 1909

The Choralcelo (“heavenly Voices”) was a hybrid electronic and electro-acoustic instrument conceived as a commercial high-end domestic organ, sold to wealthy owners of large country houses in the USA. The Choralcelo was designed and developed by Melvin Severy with the assistance of his brother in law George B. Sinclair and manufactured by the ‘Choralcelo Manufacturing Co’ in Boston, Massachusetts.
Melvin Severy b.1863 Melrose, Mass; d. California 1951

Melvin Severy b.1863 Melrose, Mass; d. California 1951 

Severy was a versatile inventor, engineer musician, composer and author. Before the Choralcelo, Severy’s inventions already included patents for printing presses, solar heating systems, a camera, fluid drives, and many others.The Choralcelo was developed by Severy from 1888 until 1909 when it was first presented to the public in Boston, Mass. The company was taken over in 1918 by Farrington. C. Donahue & A. Hoffman (in some reports claimed as its inventor). At least six of the instruments were sold and continued to be used up unit the 1950′s. Two working examples of the instruments are known to have survived in the USA one at Ruthmere Mansion in Elkhart, Indiana.The Choralcelo was a direct contemporary of the Telharmonium, though not as big, was still a huge instrument using a similar electromagnetic tone wheel sound generation to the Telharmonium used in the ‘organ’ section of the instrument as well as a set of electromagnetically operated piano strings.
Choralcelo at Denver Collorado

Part of a Choralcelo at Denver Collorado


The visible part of the Choralcelo consisted of two keyboards, the upper (piano) keyboard having 64 keys and the lower 88 (piano and ‘organ’), controlling the invisible part of the instrument, usually in the basement of the house, consisting of 88 tone wheels and a set of piano strings and bells that were vibrated by electromagnets and a set of hammers. The keyboards also had a set of organ style stops to control the timbre and fundamentals of the tone that could then be passed through cardboard, hardwood, softwood, glass, steel or “bass-buggy” spring resonators to give the sound a particular tone.The Choralcelo also incorporated a pianola style paper roll mechanism for playing ‘pre-recorded’ music and a 32 note pedal board system. The entire machine could occupy two basements of a house, the keyboards and ‘loudspeakers’ being the only visible part of the instrument.

Promotional brochure from the  Choralcelo Manufacturing Co

Detailed History of the Choralcelo from “History Of the Choralcelo” by W.Jenkins

“The information furnished is based on forty years of acquaintance with the instrument, and on three complete Choralcelo instruments at hand, friendship with one of the principals, interviews with others involved in the work, family members, original blueprints, all the patents issued, (and there were many) and original documents from the archives. “

“The story of the Choralcelo is largely the story of two men… Melvin L. Severy, born in 1863 in Melrose, Mass; died in California in 1951; and Wilber E. Farrington, born 1869, died 1945. Severy was a brilliantly gifted, multi-faceted inventor who secured patents on a printing press, solar heating, a camera, fluid drive, and many others, besides the Choralcelo. He was a scholar, artist, musical composer, and author. His grandson recalls that he was interested in secret passages in the pyramids, to name one of his many interests.Severy was assisted in his experimentation by his brother-in-law, George B. Sinclair. They had married Flint sisters. Wilber Farrington was an idealistic, philosophic visionary who devoted the majority of hsi life to his love of the unique tone of the novel instrument and his determination to see it successfully developed and manufactured. He was a charismatic and effective fund raiser and invested his own fortune in the work.There had been many efforts at strengthening or lengthening the tone of piano strings electrically.

Remains of a Choralcelo at the National Music Museum, Vermilion Sands, South Dakota

Remains of a Choralcelo at the National Music Museum, Vermilion Sands, South Dakota

As early as 1876, Elisha Gray had patented a single note oscillator; and in 1890 Eli C. Ohmart filed a patent on prolonging the tone of piano strings electromagnetically… the patent was assigned to Melvin Severy.The principle being worked on was simple… magnets were placed behind the strings of the piano, and accurately timed pulses of DC current were fed to the magnets coinciding with the natural periodicity of the strings.. for example, if note A vibrated at 440 vibrations per second, then 440 pulses of current per second would be fed to the magnets for that note, and sustained organ-like tone would be produced without the use of the hammers. The mechanism which accomplished this was the interruptor, powered by a small electric motor, which had nine brass cylinders 3 1/2″ long spinning at predetermined speeds. Each cylinder had eight make and break tracks 1/4 inch wide, alternate spaces being set in an enamel, a non-conductor. Sterling silver brushes rode on these tracks. The lowest notes required about 20 pulses per second, and the highest, about two thousand. The overwhelmingly difficult part was the governing of this device… the very slightest deviation and the frequency of the pulses would not coincide with the natural periodicity of the strings, and the tone will die. Patent after patent was filed for variations on governing mechanisms, some of them so elaborate that they were complicated mechanisms in themselves.

The basic concept of tone production, though simple, proved nearly impossible in execution… matching, on one side, an already tuned vibrating body, with perfectly matching pulses of magnetism, ranging anywhere from 20 vibrations per second to 2,000. The governing device controlling the speed of the make and break cylinders would not only have to provide such absolute perfection whenever called for, but would also have to be able to compensate for the vagaries of the electric current generated in that day, which powered the motor the drove the governor… to do this, it would have to be able to keep the cylinders rotating without the slightest deviation even if the motor driving the assembly slowed down or speeded up. If the speed of the cylinders changed while the instrument was being played, the tone would die out.

Remains of a Choralcelo at the National Music Museum, Vermilion Sands, South Dakota

Remains of a Choralcelo at the National Music Museum, Vermilion Sands, South Dakota

An elegantly simple, brilliant magnetic combination governor and clutch evolved, which performed perfectly without physical contact, so there could be no overheating, and there were no clutch pads or other friction assemblies to wear out. Even today it is a marvel of brilliant application of principles of physics , and a marvel at least to those who are aware of what they are seeing to watch the spinning copper band drive the heavy flywheel merely by cutting through the invisible magnetic force. It is so disarmingly simple one could have no inkling of the years of labor which preceded it. Appreciating what it represents, I still have a feeling of awe. I doubt there has ever been anything like it, before or since. It was through the many mechanisms Severy labored over and patented in his determination to solve the problem that fluid drive evolved. The first concert was given in 1905, and was by invitation. The Choralcelo of that first phase of development was an impressive upright piano with one keyboard, usually with a roll player; the case of the finest grain mahogany with beautifully hand-carved openwork scroll panels. The tone could be varied by means of a slider near the left hand. It was the first tone produced without physical contact of some kind, and the tones produced invoked orchestral instruments minus the sound of the bow on the string or the breath of the flutist.


Development continued and a two manual instrument marked the second level, or phase, of the evolution of the Choralcelo. It still had the piano keyboard and piano strings which were excited by magnets. The piano strings were tuned by means of screws to attain greater stability. There was an organ keyboard above the first one, and a row of stops to control the range of tone units. These took the form of sets of tuned bars, or plates, which could be of steel, or wood, or aluminum, or sometimes glass. There were usually 41 to a set, and typically they varied in length from 5 3/4″ to 10 1/2″, and usually were about 5/16″ thick. Materials other than steel had small iron armatures affixed so that there would be response to the magnets.


Installed directly over these bars were resonating chambers, usually cylindrical fiber tubes, open at each end, which reinforced the tone, just as one sees in marimbas and vibraharps, The tone production was entirely acoustic; there was nothing electronic about the Choralcelo… no amplifiers, no loud speakers, no tubes… nothing of the sort. These sets of bars were remote from the main console and could be placed anywhere. The switching and control devices were remote from the main console and could be contained in two cabinets, each about 5 1/2′ high, and installed in the basement, along with the interrupter mechanism and motor-generator which delivered 30 volts of DC. The bar units could also be installed in the basement if desired, in which case grillwork was installed in the floor above them to transmit the sound; or they could be installed in the music room where the console was and concealed behind panelling or whatever was desired. The units were all connected by cables, usually armored with interwoven wire strands to protect them from damage. If all the machinery and also the bar units were to be placed in the basement, the space required would be approximately that of a modest bedroom.


The final phase of the development of the Choralcelo was the rewiring of the controls so that upper partials could be at the command of the Choralcelist and thus the potential of the instrument was greatly expanded because infinite variations and combinations were now available. The attempt to produce a completely new, unique instrument of this complexity in such a short period of time… the original factory closed in 1917 because of the war… was a monumental undertaking, and the multiplicity of the directions one might take was daunting. After all, the piano metamorphosed over several centuries, and other instruments have done the same. Experiments were conducted with reeds. A magnificent, large double bass unit having steel ribbons instead of individual strings was developed… there was a remote full-sized string unit which could be remotely placed… A variation of the interrupter mechanism was developed using brass discs instead of the earlier cylinders. There were twelve discs, each with six tracks, rotating at speeds determined by the gearing. All of these inventions, some of which were superseded by later ones, required designing, engineering, machining.. the investment was astronomical. In today’s money it amounted to many hundreds of millions of dollars. The instruments themselves were expensive, by today’s standards costing about a half million.

There were about one hundred built, many of them being installed in the music rooms of the wealthy. There were some that were in theatres to accompany silent films… Filene’s in Boston had two, one in the restaurant. Lord and Taylor in New York, and Marshall Field in Chicago, among others, featured Choralcelos, as did several hotels. There were even two on yachts.

The effort was a daunting task but great strides had been made by the time WWI broke out… materials were no longer available and as a result, the factory closed. Farrington and several of the most devoted men involved remained active in several locations, Cleveland, Chicago, Port Chester, Connecticut, and New York among them. The last activity was a demonstration studio in New York City, but another world war broke out and the studio closed in 1942.”

Choralcelo Patent Files

The ‘Rangertone Organ’. Richard H.Ranger, USA, 1932

Richard Ranger at the Rangertone Organ

Richard Ranger at the Rangertone Organ

The Rangertone Organ was a large electronic tone-wheel based organ developed by the electronics engineer and pioneer of audio recording Richard Ranger in the 1930′s. The instrument was marketed by Ranger from his own company ‘Rangertone Incorporated’ on Verona Ave. in Newark, NJ. Very few of the instruments were sold, one of which was installed at the Recital hall of Skinner Hall of Music, Vassar College. After the failure to sell the instrument Ranger went on to develop a series of high fidelity phonograph devices that never went into production. During WW2 Ranger spent time investigating German electronic equipment for the US Army and it was here that he picked up and removed for his own use the German AEG Magnetophone tape recorder. Ranger returned to the U.S. and in 1947 announced his new Rangertone Tape recorder, based on the Magnetophone, which finally gave the Rangertone Inc the financial success it needed until squeezed out of the domestic market by larger companies such as Ampex.


AEG Magnetophone. The first tape recorder, Germany 1944

Richard Ranger with the  wireless facsimile system

Richard Ranger with the wireless facsimile system. in 1924, Richard Ranger invented the wireless photoradiogram, or transoceanic radio facsimile, the forerunner of today’s fax machines. A photograph of President Calvin Coolidge sent from New York to London in November 1924 became the first photo picture reproduced by transoceanic radio facsimile.

The Rangertone Organ was one of the early tone wheel organs, similar to the Hammond Organ and much earlier Telharmonium (1906). Uniquely, the Rangertone Organ had its pitch stability controlled by tuning forks, therefore it was possible to change the temperament by changing the tuning of the forks. Timbre was controlled by push-buttons to the right of the keyboard, and/or by switching between six different amplifier/speaker combinations, which had different tremolo and tonal qualities.The original version was a huge machine, with more than 150 valves. A portable single-keyboard model was built for concert performance.
Ranger made the first public demonstration of his huge  ‘pipeless organ’ at Newark, New Jersey in 1931.
Press telegram announcing Ranger's new instrument

Press telegram announcing Ranger’s new instrument in 1931

Pitch controls of the Rangertone Organ

Pitch controls of the Rangertone Organ

“Ranger’s apparatus consisted essentially of twelve separate sets of motor-driven alternators precisely maintained at given rotational speeds, by tuning-fork control apparatus. One of these sets of alternators, as shown in Fig. 5, generated all the required C’s; another all the C sharps; another the D’s, and so forth. From these alternators he obtained all the desired fundamentals and their true harmonic frequencies for the tempered scale. Timbre control switches selected the partials and their amplitudes for any desired tone quality. Amplifiers were, of course, used with reproducers to translate the feeble audio currents into sound.

Ranger’s improvements over the basic work of Cahill were made possible by the advent of the vacuum tube. For example, he provides means for automatic selection of different amplifiers, for different simultaneously produced tones, to prevent cross modulation in a single amplifier; means for avoiding keying transients, for accentuating high or low frequencies, for restricting tremolo to specific components of a complex tone, and at different tremolo rates, means to provide glissando effects, for regulating the temperament, for providing damped wave trains in simulation of percussive tones, and numerous other details.”

Proceedings of the institute of Radio Engineers November 1936 Volume 24

Richard Howland Ranger 1899, Indianapolis, Indiana, d 1961

Richard Howland Ranger 1899, Indianapolis, Indiana, d 1961


Biographicall details by: Dr. David L. Morton, Jr. Research Historian IEEE Center for the History of Electrical Engineering
Proceedings of the institute of Radio Engineers November 1936 Volume 24
ELECTRONIC MUSIC AND INSTRUMENTS. By Benjamin F. Miessner. (Miessner Inventions, Inc., Millburn, New Jersey)

The ‘Hammond Organ’. Laurens Hammond, USA, 1935

The original Hammond Organ was Designed and built by the ex-watchmaker Laurens Hammond and  John M Hanert in April 1935. Hammond set up his ‘Hammond Organ Company’ in Evanston, Illinois to produce electronic organs for the ‘leisure market’ and in doing so created one of the most popular and enduring electronic instruments ever built. Hammond’s machine was designed using technology that relates directly to Cahill’s ‘Telharmonium’ of 1900, but, on a much smaller scale. The Hammond organ generated sounds in the same way as the Telaharmonium, the tone wheel-The tone generator assembly consisted of an AC synchronous motor connected to a gear train which drove a series of tone wheels, each of which rotated adjacent to a magnet and coil assembly. The number of bumps on each wheel in combination with the rotational speed determined the pitch produced by a particular tone wheel assembly. The pitches approximate even-tempered tuning.
This method of creating tones was maintained  until the mid 1960′s when transistors replaced tone wheels
The Hammond had a unique drawbar system of additive timbre synthesis (again a development of the Telharmonium) and stable intonation – a perennial problem with electronic instruments of the time. A note on the organ consisted of the fundamental and a number of harmonics, or multiples of that frequency. In the Hammond organ, the fundamental and up to eight harmonics were available and were controlled by means of drawbars and preset keys or buttons.A Hammond console organ included two 61-key manuals; the lower, or Great, and upper, or Swell, and a pedal board consisting of 25 keys. The concert models had a 32-key pedalboard. Hammond also patented an electromechanical reverb device using the helical torsion of a coiled spring, widely copied in later electronic instruments.As well as being a successful home entertainment instrument, The Hammond Organ became popular with Jazz, Blues and Rock musicians up until the late 1960′s and was also used by ‘serious’ musicians such as Karheinz Stockhausen in “Mikrophonie II”

Hammond patent documents