While many electronic instruments and synthesis methods have become commonplace, a fascinating array of rare and unconventional approaches have emerged, often fading into obscurity despite their ingenuity. We will explore these lesser-known synthesis methods, their inventors, and their place in the evolution of electronic music.

Early Innovations (Late 19th - Early 20th Century)

The dawn of electronic music synthesis can be traced back to the late 19th century. One of the earliest and most ambitious attempts was the Telharmonium, developed by Thaddeus Cahill in 1897. This massive instrument, weighing 200 tons, used rotating electromagnetic tone wheels to generate electrical signals, which were then converted to sound. Despite its innovative approach, the Telharmonium's size and power consumption made it impractical for widespread use.

As the 20th century began, new ideas in sound synthesis emerged. The Optophonic Piano, invented in 1916 by Russian futurist painter Vladimir Baranoff-Rossine, was a groundbreaking attempt at audiovisual synthesis. It combined sound generation with colored light projections, using rotating discs and light sensors. This early foray into multimedia art presaged later developments in audiovisual performance.

The Interwar Period: Electrical and Optical Innovations

The period between World Wars I and II saw a flourishing of new synthesis ideas. The Spherophone, invented by Jörg Mager in the 1920s, used capacitance changes to generate sounds, allowing for precise control of microtonal intervals. Similarly, the Croix Sonore (Sonorous Cross), created by Russian musician Nikolai Obukhov in 1926, utilized electromagnetic fields and the performer's body capacitance for pitch and volume control.

1929 saw the introduction of the Trautonium by Friedrich Trautwein in Germany. This instrument used neon tubes for sound generation and featured a unique resistor wire interface for controlling pitch. While not widely adopted, it found use in some film scores and influenced later electronic instruments.

Optical sound synthesis also emerged during this period. The ANS Synthesizer, developed by Russian inventor Evgeny Murzin between 1938 and 1957, used a revolutionary photo-optic system. It generated sound by scanning drawn images, effectively turning visual information into audio. This rare synthesis method found application in Soviet-era films and experimental music.

Post-War Developments: Pushing Boundaries

The aftermath of World War II brought new experimentation in sound synthesis. The Oramics system, developed by Daphne Oram (co-founder of the BBC Radiophonic Workshop) in 1957, allowed for the creation of electronic sounds by drawing directly onto film. The drawn shapes were then read by photoelectric cells and converted into sound, offering unprecedented control over various sound parameters.

In the realm of electro-acoustic instruments, Hugh Le Caine's Electronic Sackbut (1945-1973) stands out. This monophonic instrument, considered one of the first voltage-controlled synthesizers, offered touch-sensitive controllers for volume, pitch, and timbre, presaging later developments in synthesizer design.

The Clavivox, invented by Raymond Scott in 1952, combined a keyboard with a theremin-like pitch control, creating a unique hybrid instrument. Scott, a pioneer in electronic music and instrument design, also created the Electronium (1959-1977), an early attempt at an algorithmic composition machine.

Obscure but Influential: Late 20th Century Innovations

As electronic music became more mainstream, some inventors continued to explore unconventional synthesis methods. The Buchla 100 series (1963), created by Don Buchla, introduced the concept of voltage control and modular synthesis, offering a different approach to sound creation compared to the more commercially successful Moog synthesizers.

The Crystal Radio Oscillator technique, while not an instrument per se, represents an innovative approach to sound generation. By feeding the output of a crystal radio back into itself, experimental musicians have created simple but unique tones, turning a basic radio receiver into a sound synthesis tool.

Michel Waisvisz's The Hands (1984) is another example of unconventional synthesis. This wearable instrument used an array of sensors to translate hand movements into sound, pioneering new forms of gestural control in electronic music.

The Digital Age and Beyond

Even in the digital age, inventors continue to explore novel synthesis methods. The Reactable (2003), developed by a team at Pompeu Fabra University, uses a tangible user interface where physical objects on a tabletop surface control various synthesis parameters, blending digital technology with physical interaction.

More recently, instruments like the Tenori-on (2005) by Toshio Iwai have explored grid-based interfaces for sound creation and sequencing, while the Eigenharp (2009) has pushed the boundaries of expressive control in digital instruments.

Exploring the Fringes: Lesser-Known Synthesis Techniques

While many of the instruments mentioned so far have achieved some level of recognition among electronic music enthusiasts, there exists an even more obscure realm of sound synthesis that pushes the boundaries of conventional thinking.

Biological and Natural Phenomenon-Based Synthesis

Some innovators have looked to nature and biological processes for inspiration in sound creation. The Biometric Orchestra, conceptualized by Benoit Maubrey in the 1980s, used biosensors to convert performers' physiological data into sound. This approach blurs the line between the human body and the instrument.

Similarly, the Photosynthesizer, developed by Matthew Tate in 2012, uses the electrical output from living plants to generate sound. This unique approach not only creates interesting timbres but also raises questions about the nature of "live" performance.

Geological Synthesis

The Earth Harp, invented by William Close in 1999, turns architectural structures and landscapes into musical instruments. By stretching long strings over canyons or attaching them to buildings, Close creates massive stringed instruments that produce deep, resonant tones.

The Stalacpipe Organ, found in Luray Caverns, Virginia, is another geological marvel. Created by Leland W. Sprinkle in 1954, it uses electronically controlled rubber mallets to strike stalactites, producing melodic tones from the natural formations.

Meteorological Synthesis

Some artists have harnessed weather phenomena for sound creation. The Aeolian Harp, while an ancient concept, has been reimagined by modern artists. These instruments use wind to create ethereal, ever-changing soundscapes.

The Singing Ringing Tree, a wind-powered sound sculpture created by architects Mike Tonkin and Anna Liu in 2006, takes this concept further. Located in Lancashire, England, this tree-shaped structure produces an otherworldly chorus as the wind passes through its pipes.

Quantum Synthesis

Pushing into the realm of quantum physics, researchers at the National Institute of Standards and Technology created the "Quantum Microphone" in 2019. This device can detect the smallest known unit of sound, a phonon, potentially opening up new realms of sound synthesis at the quantum level.

Artificial Intelligence and Machine Learning in Synthesis

While not entirely "rare," the use of AI and machine learning in sound synthesis represents a cutting-edge approach. Google's NSynth (Neural Synthesizer) uses machine learning algorithms to create new sounds by analyzing and combining the characteristics of existing instruments.

Similarly, the AI-augmented modular synthesizer system developed by Dadabots and Teenage Engineering in 2021 uses neural networks to generate patches and sequences, creating a hybrid human-AI instrument.

Early Innovations (Late 19th - Early 20th Century)

1. Telharmonium (1897): Developed by Thaddeus Cahill, this massive 200-ton instrument used rotating electromagnetic tone wheels to generate electrical signals, which were then converted to sound. Despite its innovative approach, its size and power consumption limited its adoption.
2. Optophonic Piano (1916): Invented by Russian futurist painter Vladimir Baranoff-Rossine, it combined sound and colored light, using rotating discs and light sensors to create both visual projections and audible tones.
3. Theremin (1920s): While relatively well-known, the Theremin remains rare in mainstream music. Invented by Léon Theremin, it uses two metal antennas to sense the position of the player's hands, controlling pitch and volume without physical contact.
4. Spherophone (1920s): Invented by Jörg Mager, this instrument used capacitance changes to generate sounds, allowing for precise control of microtonal intervals.
5. Ondes Martenot (1928): Created by Maurice Martenot, this electronic instrument combines a keyboard with a sliding metal ring worn on the right index finger. It's known for its expressive capability and unique timbre.
6. Trautonium (1929): Invented by Friedrich Trautwein in Germany, it used neon tubes to generate sound and featured a unique resistor wire interface for controlling pitch.
7. Croix Sonore (Sonorous Cross) (1926): Created by Russian musician Nikolai Obukhov, this instrument utilized electromagnetic fields and the performer's body capacitance for pitch and volume control.

Mid-20th Century Developments

8. ANS Synthesizer (1938-1957): Developed by Russian inventor Evgeny Murzin, it used a unique photo-optic system to generate sound by scanning drawn images.
9. Electronic Sackbut (1945-1973): Created by Hugh Le Caine, this monophonic instrument is considered one of the first voltage-controlled synthesizers, offering touch-sensitive controllers for volume, pitch, and timbre.
10. Clavivox (1952): Invented by Raymond Scott, it combined a keyboard with a theremin-like pitch control, creating a unique hybrid instrument.
11. Cristal Baschet (1952): Developed by Bernard and François Baschet, this acoustic instrument consists of metal rods vibrated by friction, amplified by fiberglass cones.
12. Electronium (1959-1977): Also created by Raymond Scott, this was an early attempt at an algorithmic composition machine.
13. Oramics (1957): Developed by Daphne Oram, this technique created electronic sounds by drawing on film, which was then read by photoelectric cells.
14. Stalacpipe Organ (1954): Created by Leland W. Sprinkle in Luray Caverns, Virginia, it uses electronically controlled rubber mallets to strike stalactites, producing melodic tones from natural formations.
15. Mellotron (1963): While influential in 1960s and 70s music, it's rare in modern production. It uses pre-recorded tape loops triggered by a keyboard.
16. Buchla 100 series (1963): Created by Don Buchla, it introduced the concept of voltage control and modular synthesis, offering a different approach to sound creation compared to Moog synthesizers.
17. Stylophone (1967): Invented by Brian Jarvis, this small, stylus-operated synthesizer became a novelty instrument but has been used in some popular music.

Late 20th Century and Beyond

18. Waterphone (1960s): Invented by Richard Waters, this acoustic instrument consists of a stainless steel resonator bowl with bronze rods of different lengths around the rim, played with mallets or a bow.
19. Kraakdoos (Cracklebox) (1960s): Developed by Michel Waisvisz, this small box with six metal contacts produces sounds when the player's skin completes the circuit between the contacts.
20. The Hands (1984): Also created by Michel Waisvisz, this wearable instrument used an array of sensors to translate hand movements into sound.
21. Daxophone (1987): Invented by Hans Reichel, this electric wooden experimental instrument is played by bowing a thin wooden blade connected to a sound box.
22. Earth Harp (1999): Invented by William Close, it turns architectural structures and landscapes into musical instruments by stretching long strings over large distances.
23. Reactable (2003): Developed by a team at Pompeu Fabra University, it uses a tangible user interface where physical objects on a tabletop surface control various synthesis parameters.
24. Tenori-on (2005): Created by Toshio Iwai, this digital instrument features a 16x16 grid of LED buttons for real-time composition and performance.
25. Eigenharp (2009): This highly expressive electronic instrument combines keys, pads, and breath control for complex performances.

Unconventional and Experimental Methods

26. Crystal Radio Oscillator synthesis: This technique involves feeding the output of a crystal radio back into itself to create simple but unique tones.
27. Biometric Orchestra (1980s): Conceptualized by Benoit Maubrey, this used biosensors to convert performers' physiological data into sound.
28. Photosynthesizer (2012): Developed by Matthew Tate, this uses the electrical output from living plants to generate sound.
29. Singing Ringing Tree (2006): Created by architects Mike Tonkin and Anna Liu, this wind-powered sound sculpture in Lancashire, England, produces an otherworldly chorus as wind passes through its pipes.
30. Aeolian Harp: An ancient concept with modern applications, these instruments use wind to create ethereal, ever-changing soundscapes.
31. Hydraulophone (2000s): Invented by Steve Mann, this instrument produces sound from water in motion, often integrated into public fountains.
32. Pyrophone (Fire Organ) (1875): Invented by Georges Frédéric Eugène Kastner, this organ uses combustion to produce musical tones.
33. Cloud Chamber Bowl (1950): Created by Harry Partch, this instrument consists of pyrex bowls suspended from a wooden frame and struck with mallets.
34. Laser Harp (1980s): Popularized by Jean-Michel Jarre, this instrument uses laser beams to trigger musical notes when the beams are interrupted.
35. Marble Machine (2016): Created by Martin Molin of the band Wintergatan, this mechanical music device uses marbles to trigger instruments and create melodies.
36. Glass Armonica (1761): Invented by Benjamin Franklin, this instrument consists of rotating glass bowls played by touching them with moistened fingers.
37. Zeusaphone (Singing Tesla Coil) (2007): This instrument uses Tesla coils to produce musical tones through electrical discharges.
38. Quantum Microphone (2019): Developed by researchers at the National Institute of Standards and Technology, this device can detect the smallest known unit of sound, a phonon, potentially opening up new realms of sound synthesis at the quantum level.
39. AI-augmented modular synthesizer (2021): Developed by Dadabots and Teenage Engineering, this system uses neural networks to generate patches and sequences, creating a hybrid human-AI instrument.
40. Orchestrion (early 20th century): A mechanical musical instrument designed to imitate the sound of an orchestra, often using piano rolls to control various instruments.