American Innovations in Electronic Musical Instruments

American Innovations in Electronic Musical Instruments

Keyboard and Tactile Interfaces With the notable exception of the theremin, discussed elsewhere, all early electronic musical instruments were primarily controlled by a keyboard, frequently the standard 12-tone (chromatic) layout we know from the acoustic piano. The first true electronic instrument was developed by American telegraph innovator Elisha Gray, who invented the telephone independently of… Read more »

Written By

Joseph A. Paradiso

Keyboard and Tactile Interfaces

With the notable exception of the theremin, discussed elsewhere, all early electronic musical instruments were primarily controlled by a keyboard, frequently the standard 12-tone (chromatic) layout we know from the acoustic piano. The first true electronic instrument was developed by American telegraph innovator Elisha Gray, who invented the telephone independently of Alexander Graham Bell, but got to the Patent Office slightly later (he nonetheless went on to form the company that became Western Electric). In 1876, he developed the Musical Telegraph, an array of tuned, self-oscillating reeds (similar to modern electronic buzzers) that were activated by switches on a musical keyboard.

The all-time award for sheer mass in an electronic musical instrument, however, has to go to Thaddeus Cahill. In 1906, he created the first Telharmonium in Holyoke MA, subsequently transporting it in 30 railroad cars to Telharmonium Hall on 39th Street and Broadway in New York City. This 200-ton instrument generated musical audio from a building full of tuned dynamo wheels; one per note. As his instrument presaged vacuum tube amplification, the dynamos themselves each needed to generate the circa 10 kW required to directly drive the transducers of thousands of listeners who subscribed over telephone lines. As one might expect, these large signals, flowing through many common wires in a bundled telephone line, tended to interfere with conventional voice calls, making the Telharmonium somewhat controversial. This property, together with the development of vacuum tube circuitry, led to the decommissioning of the third and last Telharmonium in 1916.

The Telharmonium was controlled from a multiple-keyboard console designed to accommodate two players. Cahill’s keyboard was actually touch-sensitive (a feature lacking in most of its descendants in the electronic organ world); as each key was connected to a mechanism that adjusted the alignment of two coils in a coupling transformer, the amplitude of the signal was a function of the key depression. Cahill also designed a 36-note per octave keyboard to enable performances in just intonation, and the Telharmonium sported switches and pedals to control the instrument’s timbre and dynamics. Since there was one tone wheel per note, the Telharmonium was a polyphonic instrument. Three decades later, the Teleharmonium’s electric tonewheel progeny were miniaturized, combined with vaccuum tube amplification, and commercialized as the Rangertone and Hammond organs. Although the Rangertone had very limited commercial success (Richard Ranger went on to develop successful magnetic tape recorders), the organs made in Evanston, Illinois by Laurens Hammond left an indelible mark in music history.

The Choracello, developed by Melvin Severy in 1909, was a hybrid instrument. While it likewise generated organ sounds from tone wheels, the Choracello also had a set of strings that could be hammered as in a conventional piano or electromagnetically excited, as in the e-bows used by today’s guitarists. The output sound could be passed through a variety of mechanical resonators, allowing different timbres to be selected from a set of stop switches. Since the Choracello only occupied two rooms, it was perhaps the first “home organ”. At least six of them were built and sold by the Choracello Manufacturing Company in Boston MA.

The first application of vacuum tubes to music was made by the famous developer of the triode (the tube configuration that launched active electronics), Lee DeForest. His 1915 Audion Piano pioneered the use of heterodyned oscillators as audio sources, a technique that continued to be used in electronic musical instruments for the next two decades. The Audion Piano, which DeForest demonstrated at public events in the New York area, was played through a musical keyboard that was only partially polyphonic; e.g., it was able to produce one note at a time for each octave of keyboard.

Most of the early vacuum tube instruments were totally monophonic. The few exceptions that featured full polyphony, such as Hugo Gernsback’s Pianorad (built in 1926 at Radio News Laboratories in New York), or Hammond’s Novachord (1939) required a huge bank of bulky tube oscillators (one per note), which were notorious for drifting out of tune. Of special interest are the various instruments of Harold Bode, such as the Warbo Formant Organ, built in Cologne Germany in 1937. This device featured a top-note priority assignment of four vaccuum tube oscillators, allowing dynamic 4-voice polyphony to be allocated in the fashion of modern synthesizers. Although Bode’s original instruments were developed in Germany, he later emigrated to the USA, where he went on inspire the development of modular synthesis and signal processing, while designing devices like frequency-shifters and vocoders.

Several monophonic tube-driven keyboard instruments were built in the USA, such as Hammond’s SoloVox in 1940 and Nicholas Langer’s 1932 Emicon, which used gas discharge tube oscillators (pioneered in Germany by Friedrich Trautwein in his 1928 Trautonium). The French monophonic keyboards, such as Maurice Martenot’s 1928 Ondes Martenot and George Jenny’s 1941 Ondioline, were truly dexterous performance instruments, as they sported several continuous and discrete controllers that could be articulated by the left hand and knee while the right hand played a melody. This configuration persists in today’s MIDI keyboards.

Although never produced commercially, the instruments of Canadian electronic music pioneer Hugh LeCaine represented important milestones in the field of electronic musical interfaces. The best-known of his inventions is a very expressive device termed the Electronic Sackbut (named after the medieval forerunner to the trombone), produced in 1948 as an electronic instrument capable of emulating the sonic complexity of acoustic instruments. The Sackbut was a monophonic keyboard with several channels of articulation control. The volume and attack of a sound were determined by the displacement and pressure of the keys and the position of a foot pedal. The keys could also move horizontally, changing the note’s pitch, plus another foot pedal controlled the amount of portamento between notes; pitch could also be altered through a touch-sensitive strip mounted above the keyboard. LeCaine designed an extremely dexterous timbre controller for the left hand, with the thumb controlling a pair of formant resonances, the index finger manipulating a capacitive “joystick” mixer that adjusted the basic oscillator waveshape, and the outer three fingers introducing different types of frequency modulation. With all of these continuous input channels available, the Sackbut came alive in the hands of a trained performer, as can still be heard in LeCaine’s recordings.

Although the popular voltage-controlled analog synthesizers of the late 1960’s and early 1970’s (made by Moog, Arp, E-Mu, etc.) were capable of being controlled through essentially any means, the dominant interface was again a simple diatonic keyboard. These keyboards generated a logic gate while a key is pressed and grabbed a voltage off a (usually linear) resistor ladder with a sample-hold; the rising gate triggered envelope generators that controlled the dynamics, while the keyboard’s sampled voltage determined the pitch, filter tracking, etc. The majority of these keyboards were monophonic, although there were some duophonic varieties that produced a pair of control voltages when two keys were hit. These keyboards were also usually inexpressive; very few of them responded to velocity, pressure, or anything besides key hits. Continuous control of dynamics in these devices was obtained by turning knobs, pushing pedals, or manipulating something like a ribbon controller (a position-sensitive resistive strip that responded to finger touch), again primarily with the left hand.

Responding to the demand for a portable synthesizer that could be easily brought on tour with a gigging band, Moog music released the famous MiniMoog in 1970, a device that had enormous influence on synthesizers to follow. This instrument was a hardwired subset of the large modular systems available before; signal routing between components was controlled entirely by a set of switches and potentiometers. No patchcords or impressive bank of equipment was needed, although this portability and affordability was achieved by compromising flexibility and sonic variety. Economics couldn’t argue with this, however. Since the MiniMoog was such a success (over 12,000 were sold, more than any previous synthesizer), it cast a shadow that extends to the present day, the most obvious being the twin set of wheels to the left of nearly all electronic music keyboards (Robert Moog is often quoted as regretting not patenting this innovation). On the MiniMoog, one of these wheels controls pitch bend (thus has a center detent at the null position, with a spring return), and the other controls oscillator and filter modulation; more recent synthesizers are capable of remapping these controllers to any desired function. Nearly all of the expressive articulation in synthesizer solos from progressive rock and fusion jazz bands of the 1970’s was produced by turning these wheels. Although several variations have appeared over the years, such as joysticks (becoming popular in the 1980’s synthesizers such as the Korg Poly-61 and the Sequential Prophet VS), the combination of ribbon controller and wheel in the Korg Prophecy and the 2-dimensional touchpad on the recent Korg Z1, the canonical MiniMoog thumbwheels tend to be always included.

In the early-70’s, synthesizer keyboards became polyphonic, due to the invention of the digital scanning keyboard, where each key was connected to the input of a digital multiplexer, which was continually cycled and monitored to detect changes in key state. These keyboards had a convoluted history, being originally explored by Donald Buchla, then designed into the Allen Digital Organ by Ralph Deutsch and colleagues at Rockwell International, finally reaching the mainstream synthesizer community in the keyboards designed by Dave Rossum and Scott Wedge of E-Mu Systems. When a key was pressed in one of these systems, a “voice” composed of an oscillator, envelope generator, voltage-controlled amplifier and filter are triggered accordingly if available; different kinds of polyphonic note priority could be specified. This was done entirely in hardware in the early devices (i.e., the E-Mu 4050 keyboard, later evolving into the controller for the Oberheim 4 and 8 Voice synthesizers), then in 1977 by a microprocessor in the E-Mu 4060, which was adapted a year later for the famous Sequential Prophet 5. Today, of course, keyboard scanning, note allocation, synthesis, and signal processing are all performed digitally by firmware running on the ASICs and processors embedded in modern synthesizers.

The MIDI specification, first introduced in 1983, provides for sending several descriptive parameters along with basic pitch, finally encouraging expressive keyboards to be a standard item on the commercial market. Every note is accompanied by a 7-bit velocity parameter, measured in most keyboards by clocking the amount of time it takes for a key to switch between an upper and lower contact. Many keyboards also send aftertouch (usually defined by another switch closure as the keys are pressed harder), and continuous key pressure.

There have been several relatively recent attempts to improve on the electronic music keyboard, and open more degrees of freedom to the player. The Notebender, designed by John Allen and colleagues at Boston’s Key Concepts Inc. in 1983, allows keys to move in and out after being struck, producing additional articulation. The Multiply-Touch-Sensitive keyboard, designed by Bob Moog and Thomas Rhea in the late 1980’s, goes well beyond measuring key depression and pressure; it also uses capacitive pickups on each key to measure the 2-coordinate finger positions over the key surfaces. Several commercially-made analog synthesizers of the late 60’s through mid 70’s dispensed entirely with a mechanical keyboard, and used capacitive touch plates to trigger notes. Some of the better-known examples were the portable synthesizers from Great Britain, such as the Wasp and Gnat from Electronic Dream Plant, or the Synthi-AKS from Electronic Music Systems. These devices had the image of a diatonic keyboard printed across a flat plate, under which capacitive pickups sensed finger contact through the injection of ambient pickup noise or the change in the transient response of an attached circuit. The famous synthesizer designer, Donald Buchla, initially avoided the use of keyboards, anticipating the limits they would impose on the ways in which electronic instruments would be used. Many of his early interfaces employed similar capacitive touchpads (some of which would also respond to pressure and position), although these were never intended to emulate a musical keyboard. As any pianist knows, the “action” and haptic response of a given keyboard greatly affects its playability. Although the best electronic keyboards now have a passive weighted action, their feel is generally analogous to a low-quality acoustic piano. Active force-feedback keyboards have been pursued by various researchers, including Chuck Monte (developer of the “Miracle Piano”), Claude Cadoz and collaborators in Grenoble, and Brent Gillespie at Northwestern University and Stanford’s CCRMA. These devices have position encoders and mechanical drivers on each key, thus, by programming appropriate dynamic response, they are ideally capable of emulating the feel any keyboard, from the best concert grand to totally alien devices with “impossible” mechanics.

Recent years have seen the limited introduction of entirely different keyboard layouts as electronic music controllers. The electronics giant Motorola actually built such a controller to accompany its “Scalatron” synthesizer in 1974; two of these devices were equipped with a “generalized” keyboard designed by George Secor that sported a dense array of 240 pushbutton keys for playing microtonal music, with notes lying between those of our conventional 12-tone scale. The MicroZone, produced by Starr Labs in San Diego, CA., is a MIDI keyboard designed for microtonal music, featuring an array of 768 hexagonal keys in an 8 x 96 honeycomb matrix. Other large MIDI “button bank” and switch panel interfaces have been built, such as the “Monolith” by Jacob Duringer of Lake Forest, CA., while others are under development, like the “Chordboard” by Grant Johnson of Fair Oaks, CA and John Allen’s Bosanquet-type generalized MIDI keyboard.

One of the most impressive such interfaces was designed and built by the late Sal Martirano and his colleagues at the University of Illinois in 1969. Termed the “Sal-Mar Construction”, it was a bank of 291 lightable touch-sensitive switches, connected through a massive patch bay to a combinatorial logic unit that drove a custom analog synthesizer producing up to 24 independent audio channels. The Sal-Mar was a live performance instrument, used by Martirano in many concerts and recordings. It was a very early hybrid digital/analog composition machine, where the player would define and interact with sonic sequences in real time. The New York composer Raymond Scott’s Electronum, completed in 1970, was another device of this sort, where a user could “guide” a composition interactively by manipulating a set of buttons, switches, and knobs. Another interface of this sort was Peter Otto’s 1981 “Contact Digital Audio Workstation Control,” which he made when working with Luciano Berio in Florence, designed as an array of 91 knobs, switches, and faders, with entirely programmable functions, enabling continuous control over digitally-generated music. These interfaces hearken back to the days of the large modular analog synthesizers, where there was a knob or switch (often hidden behind the patch cords) for every function. Musicians such as David Borden, Pat Gleason, Tangerine Dream, Klaus Schulze, and Keith Emerson actually took such huge, temperamental devices on the road and performed live with these modular systems, dynamically throwing patches and twiddling knobs to tweak or articulate a sound.

Even though these interfaces are big, clumsy, and expensive, having all adjustments and parameters physically arrayed about the player can speed the process of sound design. In some corners of the industry (i.e., mixing boards), such a massive, parallel, tactile interface is still considered to be essential and only slowly yields to digital GUI (Graphical User Interface) abstraction. Occasionally, music manufacturers have heeded the call to again provide large banks of parallel knobs and switches to give their synthesizers a more intuitive programming and control interface (editing sounds with only the standard few buttons, knob or two, and menu-driven LCD panel can be very tedious. An example is the PG1000, once built by Roland as a MIDI-connected front-end programmer for their D50 synthesizer. These are much less common now, being replaced by readily available graphical editor/librarian software packages that run on personal computers, interacting with synthesizers through a set of virtual GUI controls; not nearly as fast and intuitive, but much more practical. MIDI controllers that feature a smaller (but still significant) set of programmable faders and switches are still made by a few manufacturers, such as the JL Cooper FaderMaster, the E-Mu Launchpad, and the Peavey PC.

Some artists give musical performances from the standard keyboard and mouse of a desktop computer. For example, Japanese computer musician Yashuhiro Otani controls dynamic audio soundscapes in live performances only with his Macintosh keyboard and a small mixer. Laurie Spiegel’s well-known Music Mouse program, already available in the late 1980’s uses the computer mouse and keyboard for live control over rich audio textures. This trend will open up in the not-too-distant future, when we can envision quality musical performances being given on the multiple sensor systems and active objects in our smart rooms.

From American Innovations in Electronic Musical Instruments
by Joseph A. Paradiso
© 1999 NewMusicBox