The ‘Audion Piano’ and Audio Oscillator. Lee De Forest. USA, 1915

De Forest playing the Audion Piano

De Forest playing the Audion Piano

Lee De Forest , The self styled “Father Of Radio” ( the title of his 1950 autobiography) inventor and holder of over 300 patents, invented the triode electronic valve or ‘Audion valve’ in 1906- a much more sensitive development of John A. Fleming’s diode valve. The immediate application of De Forest’s triode valve was in the emerging radio technology of which De Forest was a tenacious promoter. De Forest also discovered that the valve was capable of creating audible sounds using the “heterodyning”/beat frequency technique: a way of creating sounds by combining two high frequency signals to create a composite lower frequency within audible range and in so doing inadvertently invented the first true audio oscillator that paved he way for future electronic instruments and music.

Lee De Forest's Triode Valve of 1906

Lee De Forest’s Triode Valve of 1906

De Forest Created the ‘Audion Piano’, the first vacuum tube instrument in 1915 based on earlier audio experiments in 1907 and by using his invention of the triode tube as an audio oscillator  had laid the blueprint for most future electronic instruments until the emergence of transistor technology some fifty year later. The Audion Piano was the first instrument to use a beat-frequency or “heterodyning” oscillator system and also the first to use body capacitance to control pitch and timbre ( The heterodyning effect was later much exploited by the Leon Termen with his Theremin series of instruments and Maurice Martenot’s Ondes-Martenot amongst many others. ). The Audion Piano, controlled by a single keyboard manual, used a single triode valve per octave controlled by a set of keys allowing one monophonic note to be played per octave. This audio signal could be processed by a series of capacitors and resistors to produce variable and complex timbres and the output of the instrument could be sent to a set of speakers placed around a room giving the sound a novel spatial effect. De Forest planned a later version of the instrument that would have separate valves per key allowing full polyphony- it is not known if this instrument was ever constructed.
De Forest described the Audio Piano as capable of producing:

“Sounds resembling a violin, Cello, Woodwind, muted brass and other sounds resembling nothing ever heard from an orchestra or by the human ear up to that time – of the sort now often heard in nerve racking maniacal cacophonies of a lunatic swing band. Such tones led me to dub my new instrument the ‘Squawk-a-phone’….The Pitch of the notes is very easily regulated by changing the capacity or the inductance in the circuits, which can be easily effected by a sliding contact or simply by turning the knob of a condenser. In fact, the pitch of the notes can be changed by merely putting the finger on certain parts of the circuit. In this way very weird and beautiful effects can easily be obtained.”
(Lee De Forest’s Autobiography “The Father Of Radio”)

And From a 1915 news story on a concert held for the National Electric Light Association

“Not only does de Forest detect with the Audion musical sounds silently sent by wireless from great distances,but he creates the music of a flute, a violin or the singing of a bird by pressing button. The tune quality and the intensity are regulated by the resistors and by induction coils…You have doubtless heard the peculiar, plaintive notes of the Hawaiian ukulele, produced by the players sliding their fingers along the strings after they have been put in vibration. Now, this same effect,which can be weirdly pleasing when skilfully made, can he obtained with the musical Audion.”

Advert for De Forest wireless equipment

Advert for De Forest wireless equipment

De Forest, the tireless promoter, demonstrated his electronic instrument around the New York area at public events alongside fund raising spectacles of his radio technology. These events were often criticised and ridiculed by his peers and led to a famous trial where De Forest was accused of misleading the public for his own ends:
“De Forest has said in many newspapers and over his signature that it would be possible to transmit human voice across the Atlantic before many years. Based on these absurd and deliberately misleading statements, the misguided public … has been persuaded to purchase stock in his company. “
Lee De Forest, August 26, 1873, Council Bluffs, Iowa. Died June 30, 1961

Lee De Forest, August 26, 1873, Council Bluffs, Iowa. Died June 30, 1961

De Forest collaborated with a sceptical Thadeus Cahill in broadcasting early concerts of the Telharmonium using his radio transmitters (1907). Cahill’s insistence on using the telephone wire network to broadcast his electronic music was a major factor in the demise of the Telharmonium. Vacuum tube technology was to dominate electronic instrument design until the invention of transistors in the 1960′s. The Triode amplifier also freed electronic instruments from having to use the telephone system as a means of amplifying the signal.


Sources:

Lee De Forest “Father Of Radio” (Autobiography).
Wireless: From Marconi’s Black-Box to the Audion (Transformations: Studies in the History of Science and Technology) 2001 author(s) Sungook Hong
Lee de Forest: King of Radio, Television, and Film 2012. Mike Adams (auth.).
Theremin: Ether Music and Espionage. By Albert Glinsky
Electronic Music. Nicholas Collins, Margaret Schedel, Scott Wilson
Media Parasites in the Early Avant-Garde: On the Abuse of Technology and Communication. Arndt Niebisch 2012
Electric Relays: Principles and Applications. Vladimir Gurevich

The ‘Optophonic Piano’, Vladimir Rossiné, Russia and France. 1916

 

The Optophonic Piano

The Optophonic Piano

The Optophonic Piano was a one-off electronic optical instrument created by the Russian Futurist painter Vladimir Baranoff Rossiné (Born in 1888 at Kherson , Ukraine – Russia, died Paris, France 1944). Rossiné started working on his instrument c1916. The Optophonic Piano was used at exhibitions of his own paintings and revolutionary artistic events in the new Soviet Union, Rossiné later gave two concerts with his instrument (with his wife Pauline Boukour), at the Meyerhold and Bolchoi theatres in 1924. Rossiné was influenced by the ideas of Alexander Scriabin who connected sound and colour with music to produce a aesthetic synthesis – this current formed an important, almost mystical theme within Russian electronic music; through the photo-audio experiments of the 1930′s until the ANS Synthesiser (itself named after Alexander Nikolayevich Scriabin- ANS) in the 1940s.

Painted glass disk of The Optophonic Piano

Painted glass disk of The Optophonic Piano

Detail of painted disk

Detail of painted disk

Vladimir Rossiné left the Soviet Union in 1925, emigrated to Paris where he continued to hold exhibitions of paintings and concerts of his instrument.The Optophonic Piano generated sounds and projected revolving patterns onto a wall or ceiling by directing a bright light through a series revolving painted glass disks (painted by Rossiné), filters, mirrors and lenses. The keyboard controlled the combination of the various filters and disks. The variations in opacity of the painted disk and filters were picked up by a photo-electric cell controlling the pitch of a single oscillator. The instrument produced a continuous varying tone which, accompanied by the rotating kaleidoscopic projections was used by Vladimir Rossiné at exhibitions and public events:
bolchoiFR
bolchoiwg
“Imagine that every key of an organ’s keyboard immobilises in a specific position, or moves a determined element, more or less rapidly, in a group of transparent filters which a beam of white light pierces, and this will give you an idea of the instrument Baranoff-Rossiné invented. There are various kinds of luminous filters: simply coloured ones optical elements such as prisms, lenses or mirrors; filters containing graphic elements and, finally, filters with coloured shapes and defined outlines. If on the top of this, you can modify the projector’s position, the screen frame, the symmetry or asymmetry of the compositions and their movements and intensity; then, you will be able to reconstitute this optical piano that will play an infinite number of musical compositions. The key word here is interpret, because, for the time being, the aim is not to find a unique rendering of an existing musical composition for which the author did not foresee a version expressed by light. In music, as in any other artistic interpretation, one has to take into account elements such as the talent and sensitivity of the musician in order to fully understand the author’s mind-frame. The day when a composer will compose music using notes that remain to be determined in terms of music and light, the interpreter’s liberty will be curtailed, and that day, the artistic unity we were talking about will probably be closer to perfection…”Extract of an original text by Baranoff Rossiné (1916) Copyright ©Dimitri Baranoff Rossine 1997 – Adherant ADAGP -
Vladimir Baranoff Rossiné. Born in 1888 at Kherson , Ukraine - Russia, died Paris, France 1944

Vladimir Baranoff Rossiné. Born in 1888 at Kherson , Ukraine – Russia, died Paris, France 1944


Sources

http://www.iencheres.com/

zdocuments of the collection of Dimitri Baranoff Rossine. Copyright © Dimitri Baranoff Rossine Paris 2010

Pravda. 2002.06.20/13:21

The ‘Pianorad’, Hugo Gernsback, USA, 1926

The Pianorad at WKNY

The Pianorad at WRNY

The Pianorad was a development of the Staccatone designed by Hugo Gernsback and built by Clyde Finch at the Radio News Laboratories in New York. the Pianorad had 25 single LC oscillators,one for every key for its two octave keyboard giving the instrument full polyphony, the oscillators produced virtually pure sine tones:

Hugo Gernsbacks' Pianorad

Hugo Gernsbacks’ Pianorad

“The musical notes produced by the vacuum tubes in this manner have practically no overtones. For this reason the music produced on the Pianorad is of an exquisite pureness of tone not realised in any other musical instrument. The quality is better than that of a flute and much purer. the sound however does not resemble that of any known musical instrument. The notes are quite sharp and distinct, and the Pianorad can be readily distinguished by its music from any other musical instrument in existence.”

Each one of the twenty five oscillators had its own independent speaker, mounted in a large loudspeaker horn on top of the keyboard and the whole ensemble was housed in a housing resembling a harmonium. A larger 88 non keyboard version was planned but not put into production. The Pianorad was first demonstrated on june 12, 1926 at Gernsback’s own radio station WRNY in New York City performed by Ralph Christman. The Pianorad continued to be used at the radio station for some time, accompanying piano and violin concerts.

Hugo Gernsback

Hugo Gernsback


Sources:

Hugo Gernsback: “The ‘Pianorad’ a New Musical Instrument which combines Piano and Radio Principles” Radio News viii (1926)

The ‘Dynaphone’, René Bertrand, France, 1927

Dynaphone

The French electrical engineer René Bertrand, who had been experimenting with electronic instruments as early as 1914, was a long time friend and collaborator with Edgard Varèse and with Varèses support Bertrand developed the “Dynaphone” (not to be confused with Cahill’s “Dynamophone” or “Telharmonium”). The Dynaphone was a portable, monophonic non-keyboard, dial operated vacuum tube oscillator instrument. The instrument was semi-circular in shape with a diameter 0f 30 cm played on top of a table. The Dynaphone belonged to a family of dial-operated non keyboard electronic instruments developed around the 1930′s such as Mager’s ‘Spharaphon.The right hand controlled the pitch using a circular dial on a calibrated disc (cardboard cut-out templates of music could be inserted). The total rotation of the dial was equal to seven octaves but only the five highest or lowest could be selected at any one time by the means of a switch, giving an overlap of three octaves common to both ranges. Vibrato effects could be added by moving the right hand to and fro slightly and the machine also included a push button for articulating the sound. The left hand controlled the volume and timbre – described as similar to a cello, low flute, saxophone or french horn.

edgard

A later development of the Dynaphone (known as the ” Radio-electric-organ” used a five octave keyboard on which the note played could be doubled at the fifth and octave.The first public demonstration of the instrument in 1928 was a performance of Ernest Fromaigeat’s ‘Variations Caractéristiques’ for six Dynophones and later in ‘Roses de Metal’ a ballet by the swiss composer Arthur Honegger

In 1932 Varèse applied to the Guggenheim memorial fund for a grant towards continuing the development of the Dynaphone:

Edgard Varese

Edgard Varese

Edgarde Varèse

“…..The Dynaphone (invented 1927-28) is a musical instrument of electrical oscillations similar to the Theremin, Givelet and Martenot electrical instruments. But its principal and operation are entirely different, the resemblance being only superficial. The technical results i look for are as follows:

  • To obtain pure fundamentals
  • By means of loading the fundamentals with certain series of harmonics to obtain timbres which will produce new sounds.
  • To speculate on the new sounds that the combination of two or more interfering Dynaphones would create if combined as one instrument.
  • To increase the range of the instrument to reach the highest frequencies which no other instrument can give, together with adequate intensity.

The practical result of our work will be a new instrument which will be adequate to the creative needs of musician and musicologist…..”

Despite Varèse’s assertions, the Dynaphone was not distinctly different from its close competitors and the Guggenheim Foundation did not sponsor Bertrands work despite several further attempts by Varèse.
In 1941, Edgard Varèse, in the hope to resume his collaboration with Léon Theremin, wrote him the letter reported below (courtesy of Olivia Mattis ), but the inventor wasn’t able to read it until 1989, when musicologist Olivia Mattis, during an interview with Theremin (first emerged from Russia after 51 years), presented a copy of it. The letter is dated May 5, 1941.

Dear Professor Theremin,

On my return from the West in October I tried to get in touch with you. I wanted very much to see you again and to learn of the progress of your work. I was sorry – on my account – that you had left New York. I hope that you have been able to go on with your experiments in sound and that new discoveries have rewarded your efforts.

I have just begun a work in which an important part is given to a large chorus and with it I want to use several of your instruments – augmenting their range as in those I used for my Equatorial – especially in the high range. Would you be so kind as to let me know if it is possible to procure these and where … and in case of modifications in what they consist. Also if you have conceived or constructed new ones would you let me have a detailed description of their character and use. I don’t want to write any more for the old Man-power instruments and am handicapped by the lack of adequate electrical instruments for which I now conceive my music.

Mr. Fediushine has kindly offered to forward this letter to you.

Please let me hear rom you as soon as possible.

With cordial greetings and best wishes in which my wife joins me,

Sincerely,

Edgard Varese

P.S. If any of your assistants or collaborators are continuing your work in New York would you kindly put me in touch with them.


Sources:

Edgard Varèse L.E.Gratia: ‘La Musique des Ondes éthérées’ , Les ménestrel, xc (1928)

The ‘Cellule Photo Electrique’. Pierre Toulon & Krugg Bass, France, 1927.

Pierre Toulon's Patent for the Cellulophone

Pierre Toulon’s Patent for the Cellulophone

Invented by the French engineer Pierre Toulon aided by the electronic engineer Krugg Bass, the Cellulophone (“Cellule Photo-électrique”) made it’s debut as a prototype in France in 1927. The Cellulophone was an electro-optical tone generator instrument resembling an electronic organ controlled by two eight octave keyboards and a foot pedal board.

The sound was created by passing a light beam through slits in a vari-speed rotating disk. The single spinning disk was cut with a number of equidistant slits (54 slits for the lowest note) with different shaped masks to create varied timbres. The disks masked a light beam that flashed through the slits and on to a photoelectric cell, the speed of the rotating disk therefore determining the frequency of the output signal from a single vacuum tube oscillator.

One disk was used for all the notes of each octave therefore notes whose frequencies could not be generated by an integral number were out of tune. This system however gave the unique and unusual possibility of having a different timbres for each octave. The Cellulophone was one of a generation of instruments in the 1920-30′s using a photo-electric sound generation method; other examples being the “Licht-ton Orgel” , the “Photona” and the “Radio Organ of a Trillion Tones”. The increased sophistication and reliability of post war electronic circuitry marked the decline of light based synthesis after the 1940′s except for a few pioneers such as Daphne Oram who used a similar sytem not only to synthesise sounds but to sequence sounds.

Pierre Toulon proposed in the 1930′s a related technique of speech synthesis using fragments of optical film mounted on a rotating drum.


Sources

Donhauser, P.: Elektrische Klangmaschinen. Die in Deutschland und Österreich Pionierzeit, Boehlau Vienna 2007.

The ‘Ondes-Martenot’ Maurice Martenot, France, 1928

Ondes Martenot

Ondes Martenot

Maurice Martenot a Cellist and radio Telegraphist, met the Russian electronic engineer Leon Termen in 1923, this meeting lead him to design an instrument based on Termens ideas, the first model, the “Ondes-Martenot” was patented on the 2nd of April 1928 under the name “Perfectionnements aux instruments de musique électriques” (improvements to electronic music instruments). His aim was to produce a versatile electronic instrument that was immediately familiar to orchestral musicians. The first versions bore little resemblance to the later production models: consisting of two table mounted units controlled by a performer who manipulated a string attached to a finger ring (using the bodies capacitance to control the sound characteristics in a manner very similar to the Theremin) this device was later incorporated as a fingerboard strip above the keyboard.

Female Ondes Orchestra

Female Ondes Orchestra

Later versions used a standard keyboard.The Ondes-Martenot became the first succesfull electronic instrument and the only one of its generation that is still used by orchestras today, Martenot himself became, 20 years after its invention, a professor at the Paris Conservatoire teaching lessons in the Ondes-Martenot. The Ondes-Martenot’s success was the Theremins loss, although both used the vacuum tube oscillator as a sound source and were both monophonic, where the Theremin had a sliding scale and no fixed preset notes the Ondes-Martenot had a keyboard and a strip control for glissando and vibrato, organ like stops for preset timbres and an appearance that was familiar to any keyboard player.

Pre-set sounds on the later Ondes Martenot were:

  • Onde (O): A simple sine wave timbre. Similar in sound to the flute or ocarina.
  • Creux (C):  A peak-limited triangle wave. Similar in sound to a clarinet in high registers.
  • Gambe (G):  A timbre somewhat resembling a square wave. Intended to be similar in sound to string instruments, as the French title would suggest.
  • Petit Gambe (g): A similar but less harmonically-rich timbre than Gambe. The player can control the number of harmonics present in the signal by using a slider situated in the control drawer.
  • Nasillard (N): A timbre resembling a pulse wave. Similar in sound to a bassoon in low registers.
  • Octaviant (8): A timbre with a reinforced first harmonic whose intensity in the signal can be controlled by using a slider. This setting is analogous to the 4 foot stop in organ terminology.
  • Souffle (S): A timbre often described as white noise, but in fact pink noise of indefinite pitch.

The sound from the instrument could be output to a number of speakers or ‘Diffuseurs’ who’s physical properties further coloured the sound, the were:

  • ‘Principal’ A traditional, large loudspeaker.
  • ‘Résonance’ A loudspeaker which uses springs to produce a mechanical reverb effect.
  • ‘Métallique’ A small gong is used as the loudspeaker diaphragm to produce a ‘halo’ effect rich in harmonics.
  • ‘Palme’ An iconic lyre-shaped loudspeaker, using strings to produce sympathetic resonances.
loudspeakers

loudspeakers or Diffuseurs of the Ondes Martrnot: the Métallique, the palm and the Principal

The instrument also had a bank of expression keys that allowed the player to change the timbre and character of the sounds. A later (1938) version of the instrument featured microtonal tuning as specified by the Hindu poet Rabindranath Tagore and the musician Alain Danielou. The Ondes-Martenot was quickly accepted and became one of the few electronic instruments to be admitted to the orchestra (at least in France) and had a wide repertoire by prominent composers such as Edgard Varèse, Olivier Messian (The “Turangalîla Symphonie” and “Trois Petites Liturgies de la Presence Divine” amongst others ), Darius Milhaud , Arthur Honegger, Maurice Jarre, Jolivet and Koechlin.





Sources:

The ‘Ondium Péchadre’ H. Péchadre. France, 1930

The Ondium Péchadre was developed in France by H.C.R.Péchadre in 1930. The instrument was a monophonic heterodyning vacuum tube oscillator based instrument built into a light and portable heart shaped box, in performance the base of the instrument rested on the players knees and the instrument was supported against a table. The six octave range of the instrument was controlled by moving a pointer around a circular calibrated dial while the left hand controlled the volume of the sound with a velocity sensitive push button device. The attack and timbre of the sound wave could be altered to give a more staccato effect or softened to give a more string like sound.

The ‘Rhythmicon’ Henry Cowell & Leon Termen. USA, 1930

Henry Cowell and the Rhythmicon

Henry Cowell and the Rhythmicon

In 1916 the American Avant-Garde composer Henry Cowell was working with ideas of controlling cross rhythms and tonal sequences with a keyboard, he wrote several quartet type pieces that used combinations of rhythms and overtones that were not possible to play apart from using some kind of mechanical control- “un-performable by any known human agency and I thought of them as purely fanciful”.(Henry Cowell) In 1930 Cowell introduced his idea to Leon Termen, the inventor of the Theremin, and commissioned him to build him a machine capable of transforming harmonic data into rhythmic data and vice versa.

“My part in its invention was to invent the idea that such a rhythmic instrument was a necessity to further rhythmic development, which has reached a limit more or less, in performance by hand, an needed the application of mechanical aid. The which the instrument was to accomplish and what rhythms it should do and the pitch it should have and the relation between the pitch and rhythms are my ideas. I also conceived that the principle of broken up light playing on a photo-electric cell would be the best means of making it practical. With this idea I went to Theremin who did the rest – he invented the method by which the light would be cut, did the electrical calculations and built the instrument.”

Henry Cowell

“The rhythmic control possible in playing and imparting exactitudes in cross rhythms are bewildering to contemplate and the potentialities of the instrument should be multifarious… Mr. Cowell used his rythmicon to accompany a set of violin movements which he had written for the occasion…. The accompaniment was a strange complexity of rhythmical interweavings and cross currents of a cunning and precision as never before fell on the ears of man and the sound pattern was as uncanny as the motion… The write believes that the pure genius of Henry Cowell has put forward a principle which will strongly influence the face of all future music.”
Homer Henly, May 20, 1932


The eventual machine was christened the “Rythmicon” or “Polyrhythmophone” and was the first electronic rhythm machine. The Rhythmicon was a keyboard instrument based on the Theremin, using the same type of sound generation – hetrodyning vacuum tube oscillators. The 17 key polyphonic keyboard produced a single note repeated in periodic rhythm for as long as it was held down, the rhythmic content being generated from rotating disks interrupting light beams that triggered photo-electric cells. The 17th key of the keyboard added an extra beat in the middle of each bar. The transposable keyboard was tuned to an unusual pitch based on the rhythmic speed of the sequences and the basic pitch and tempo could be adjusted by means of levers.Cowell wrote two works for the Rythmicon “Rythmicana” and “Music for Violin and Rythmicon” (a computer simulation of this work was reproduced in 1972). Cowell lost interest in the machine, transferring his interest to ethnic music and the machine was mothballed.

Rhythmicon Discs

Rhythmicon Discs

After Cowell, the machines were used for psychological research and one example (non working) of the machine survives at the Smithsonian Institute.The Rhythmicon was re-discoverd twenty-five years after its creation by the producer Joe Meek (creator of the innovative hit single ‘Telstar’, 1961) apparently discovered abandoned in a New York pawnbrokers. Meek brought it back to his home studio in London where it was used on several recordings. This Rhythmicon was used to provide music and sound effects for various movies in the Fifties and Sixties, including: ‘The Rains of Ranchipur’; ‘Battle Beneath the Earth’; Powell and Pressburgers’ ‘They’re a Weird Mob’; ‘Dr Strangelove’, and the sixties animated TV series ‘Torchy, The Battery Boy’.The Rhythmicon was also rumoured to have been used on several sixties and seventies records, including: ‘Atom Heart Mother’ by Pink Floyd; ‘The Crazy World of Arthur Brown’ by Arthur Brown, and ‘Robot’ by the Tornadoes. Tangerine Dream also used some sequences from the Rhythmicon on their album ‘Rubicon’.
Rhythmicon Discs

Rhythmicon Discs


Sources:

“Henry Cowell: A record of his activities” Compiled June 1934 by Olive Thompson Cowell.

The ‘Sonar’ Nikolai Anan’yev , Russia, 1933

The Sonar 1933

The Sonar 1933

The “Sonar” was a monophonic heterodyning vacuum tube instrument developed by Nikolai Anan’yev at the GIMN Acoustic Laboratory in the USSR from 1930. The Sonar used the same  heterodyning principles of Termen’s Thereminvox but with the addition of a fretted fingerboard to vary the pitch of the oscillator. This addition made the Sonar more popular (at the time in the early Soviet period) with musicians than the Thereminvox due to it’s familiarity and playability. The Sonar was said to have been able to reproduce violin like timbres as well as simple speech phrases such as “mama”, “papa” as well as conventional instrumental sounds and became known for it’s use in ‘proletarian’ outdoor events. Anan’yev  gave over six hundred concerts to around five hundred thousand people with the Sonar during his lifetime.


Sources

Sensor Technology and the Remaking of Instruments from the Past. Emmanuelle Gallin, Marc Sirguy

Sound in Z: Experiments in Sound and Electronic Music in Early 20th-century Russia. Published by Walther König, Köln. Edited by David Rogerson, Matt Price. Foreword by Jeremy Deller. Text by Andrei Smirnov.

 

The ‘Saraga-Generator’ Wolja Saraga, Germany ,1931

The Saraga-Generator was developed by the electrical engineer and physicist Wolja Saraga at the Heinrich-Hertz Institut Für Schwingungsforschung in Berlin, Germany around 1931. The Saraga Generator was an unusual theatrical photo-electrical  vacuum tube instrument. The Saraga Generator was designed to be used for theatrical production where the sound would be triggered by movement in front of the instrument. The instrument consisted of a photoelectric cell mounted on the white painted inside surface of a box with a small slit cut on one face. A low voltage neon lamp was placed at some distance from the box on a stage and the performers movements interrupting the light beam caused variations in pitch. Envelope and timbre were affected by manipulating a hand held switch device, the overall volume being controlled by a foot pedal. The instrument had a tonal range of four octaves.