The ‘Analyzátor a syntezátor zvuku’ or ‘ASYZ’ Bohumil Matoušek, Antonín ka[…] & Pavel Pitrák, Czech Republic, 1971

The ASYZ 2.0 'Analyzátor a syntezátor zvuku' at the Barrandov Film Studio 1971
The ASYZ 2.0 ‘Analyzátor a syntezátor zvuku’ at the Barrandov Film Studio 1971

The ASYZ was built in the late 1960s at the ‘East European Hollywood’ Barrandov Film Studios in Prague to provide sound effects and electronic music for film productions, with the final version, the ASYZ2 completed in 1971. The instrument was designed by electronic engineers, Antonín ka [name incomplete], Bohumil Matoušek and later by the sound engineer and designer Pavel Pitrák who maintained the instrument throughout the seventies and eighties. The ASYZ remained in use until the 1990s and is now housed at the collection of the Cinepost post production company, Praha.

The original design was a keyboard-less modular type device intended to be used for processing external audio signals and for generating sound effects, the modules being connected using colour coded patch cables. The instrument was controlled by manually switching a rotary dial to select different timbres and pitches or by programming a 16 step three track sequencer, a six octave keyboard was added in the 1990s. The modules of the ASYZ included a Voltage Controlled Oscillator, white noise generator, low and high pass filters, a parametric equaliser, ring modulator, phaser, signal mixer, VCA, ADSR envelope shaper, LFO, random signal generators, envelope followers and auxiliary circuits. The output of the instrument was controlled by a small six-channel mixing console and monitored using a built-in oscilloscope.


Milan Guštar. ‘Elektrofony II’

‘ARP’ Synthesisers. Alan Robert Pearlman, USA, 1970

Front panel of the ARP 2500
Main front panel of the 1970 ARP 2500

The ARP Synthesiser company was started by the engineer and musical enthusiast Alan Robert Pearlman – hence ‘ARP’ – in 1970 in Lexington, Massachusetts, USA. Previous to ARP, Pearlman had worked as an engineer at NASA and ran his own company Nexus Research laboratory Inc., a manufacturer of op-amps (precision circuits used in amplifiers and test equipment) which he sold in 1967 to fund the launch of the ARP company in 1969. The inspiration for ARP came after he played with both Moog and Buchla synthesisers and being unimpressed by the tuning instability of the oscillators and lack of commercial focus – especially the keyboardless Buchla Box – and became determined to produce a stable, friendly, commercial electronic instrument.1Trevor Pinch, Frank Trocco, (2004) Analog Days: The Invention and Impact of the Moog Synthesizer, Harvard University Press.

“If you would like to spend your time creatively, actively producing new music and sound, rather than fighting your way through a nest of cords, a maze of distracting apparatus, you’ll find the ARP uniquely efficient . . . matrix switch interconnection for patching without patch cords…P.S. The oscillators stay in tune.”

ARP Advert 1970

The companies first product was the ARP 2500, a large monophonic modular voltage-controlled synthesiser designed along similar lines to the Moog Modular series 100. The 2500 had a main cabinet holding up to 12 modules and two wing-extension adding another six modules each. The interface was designed to be as clear as possible to non-synthesists with a logically laid out front panel and, unlike the Buchla and Moog Modular, dispensed with patch cables in favour of a series of  10X10 slider matrices, leaving the front panel clear of cable clutter. The 2500 also came with a 10-step analogue sequencer far in advance of any other modular system of the day

Despite the fact that the 2500 proved to be an advanced, reliable and user-friendly machine with much more stable and superior oscillators to the Moog, it was not commercially successful, selling only approximately 100 units.

Modules of the ARP 2500 2Peter Forrest, (1994) The A-Z of Analogue Synthesizers, Susurreal Publishing, Devon, England

Module # Type of Module Description
1002 power supply
1003 dual envelope generator This module contains two ADSR envelope generators (actually labeled “Attack”, “Initial Decay”, “Sustain”, and “Final Decay”), each switchable between single or multiple triggering. There is a manual gate button as well as a front panel input for gate/trigger and a back panel input for a sustain pedal.
1003a dual envelope generator (same as 1003, except re-positioned trigger switches and gate buttons)
1004 VCO A Voltage Controlled Oscillator with a range from 0.03Hz to 16kHz, this module can function as a VCO or an LFO. It features separate outputs for each of its five waveforms (sine, triangle, square, sawtooth, and pulse) and 6 CV (control voltage) inputs, as well as a CV input for Pulse Width Modulation.
1004p VCO This module is the same as the 1004, except each waveform has its own attenuation knob for mixing all the waveforms together. There is a separate output to for the mixed waveforms.
1004r VCO This module is the same as the 1004, except each waveform has its own rocker switch to route any or all of the waveforms to an extra mix output.
1004t VCO This module is the same as the 1004r, except it uses toggle switches.
1005 VCA andRing Modulator This module is half Voltage Controlled Amplifier and half Balanced (Ring) Modulator. It is switchable between linear or exponential voltage control, and features 11 inputs, 3 outputs, and illuminated push-buttons.
1006 VCF and VCA The Voltage Controlled Filter (24dB/octave, low-pass, with resonance) and Voltage Controlled Amplifier (switchable between linear and exponential) in one module
1012 Convenience Module This module routes two jack inputs to any of the upper ten lines of the lower matrix. (Remember, most of the patching for this instrument is done from these matrix sliders).
1016 dual noise generators This module features two random voltage generators outputting white or pink noise and two slow sample-and-hold circuits, four outputs in all.
1023 dual VCO Both oscillators feature the same waveforms as 1004 with a switch for high and low frequency ranges. There are a total of 10 control inputs and 2 audio outputs.
1026 Preset Voltage module This module contains eight manually or sequencer-driven gated control-voltages, each with two knobs sending control voltages to separate outputs. It can be connected, via the rear panel, to module 1027 Sequencer or module 1050 Mix-Sequencer.
1027 Sequencer This is a 10X3 sequencer with 14 outputs (including 10 separate position/step gates), 6 inputs, buttons for step and reset, and a knobs for pulse repetition/width, which controls the silence between the steps.
1033 Dual Delayed-Trigger Envelope Generator This module is the same as the 1003 ADSR module except it has two more knobs to control gate delay.
1036 Sample-and-Hold / random voltage
1045 Voice Module This all-in-one module contains a VCO, VCF, VCA, and two ADSR envelope generators, as well as 16 inputs, and four outputs. (Note: Most modules feature a spelling mistake “Resanance” instead of “Resonance”.)
1046 quad envelope generator This module is basically a 1003 and a 1033 combined into one module.
1047 Multimode Filter / Resonator This module features 15 inputs, 4 outputs and an overload warning light.
1050 Mix-Sequencer This module features two 4X1 mixers with illuminated on/off buttons.
3001 Keyboard This keyboard features a 5-octave, 61-note (C-C) keyboard with the bottom two octaves (C-B) reverse colored to show the keyboard split. The top half of the keyboard is duophonic. There are separate CV (1v/octave), gate, and trigger outputs for each side of the split, as well as separate panels on either side of the keyboard with controls for portamento, tuning, and pitch interval.
? Dual-Manual Keyboard Two 3001s, one on top of the other, with the bottom octave (C-B) or two octaves (C-B) of the top keyboard reverse colored to show the split.

The ARP 2600 (1971)

The ARP 2600 was designed to be a commercially viable portable, semi-modular analog subtractive synthesiser with built in modules i.e. a versatile but not-too-complicated synthesiser, targeted at the educational market; schools, universities and so-on. The inbuilt modules could be patched using a combination of patch cables or by using sliders to control internally hard wired connections:

“ARP 2600 The ultimate professional-quality portable synthesizer Equally at home in the electronic music studio or on stage, the ARP 2600 provides the incredible new sounds in today’s leading rock bands The 2600 is also owned by many of the most prestigious universities and music schools in the world Powerful. dependable, and easy to play. the 2600 can be played without patchcords or modified with patch cords. This arrangement provides maximum speed and convenience for live performance applications, as well as total programming flexibility for teaching, research composition and recording. An pre-wired patch connection(s) can be overridden by simply inserting a patchcord into the appropriate jack on the front panel.

The ARP 2600 is easily expanded and can be used with the ARP 2500 series.Renowned for its electronic superiority, the oscillators and filters in the 2600 are the most stable and accurate available anywhere Accompanied by the comprehensive, fully illustrated owner s manual, the ARP 2600 is recognized as the finest, most complete portable synthesizer made today

3 Voltage Controlled Oscillators 03 Hz to 20 KHz in two ranges Five waveforms include: variable-width pulse. triangle. sine, square, and sawtooth
1 Voltage Controlled Lowpass filter Variable resonance, DC coupled. Doubles as a low distortion sine oscillator.
1 Voltage Controlled Amplifier Exponential and linear control response characteristics
1 Ring Modulator. AC or DC coupled
2 Envelope Generators.
1 Envelope Follower.
1 Random Noise Generator. Output continuously variable from flat to -6db/octave
1 Electronic Switch, bidirectional
1 Sample & Hold with internal clock.
1 General purpose Mixer and Panpot.
1 Voltage Processor with variable lag.
2 Voltage Processors with inverters
1 Reverberation unit. Twin uncorrelated stereo outputs
2 Built-in monitoring amplifiers and speakers, with standard stereo 8-ohm headphone jack.
1 Microphone Preamp with adjustable gain
1 Four-octave keyboard with variable tuning. variable portamento, variable tone interval, and precision memory circuit.
DIMENSIONS: Console 32″ x 18″ x 9x Keyboard 35″ x 10″ x 6″ WEIGHT: 58 Ibs”  3ARP 2600 Promotional material 1971

ARP 2600 white version
ARP 2600 white version

ARP 2800 ‘Odyssey’ 1972

By the mid-1970s ARP had become the dominant synthesiser manufacturer, with a 40 percent share of the $25 million market. This was due to Pearlman’s gift for publicity – the ARP2500 famously starred in the film ‘Close Encounters of the Third Kind’ (1977) as well as product endorsements by famous rock starts; Stevie Wonder, Pete Townsend, Herbie Hanckock and so-on – and the advent of reliable, simpler, commercial instrument designs such as the ARP 2800 ‘Odyssey’ in 1972.

ARP 2800 Odyssey
ARP 2800 Odyssey

The ARP 2800 ‘Odyssey’ 1972-1981

The Odyssey was ARP’s response to Moog’s ‘Minimoog’; a portable, user-friendly, affordable performance synthesiser; essentially a scaled down version of the 2600 with built in keyboard – a form that was to dominate the synthesiser market for the next twenty years or so.

The Odyssey was equipped with two oscillators and was one of the first synthesisers to have duo-phonic capabilities. Unlike the 2600 there were no patch ports, instead all of the modules were hard wired and routable and controllable via sliders and button son the front panel. ‘Modules’ consisted of  two Voltage Controlled Oscillators (switchable between  sawtooth, square, and pulse waveforms)  a resonant low-pass filter, a non-resonant high-pass filter, Ring Modulator, noise generator (pink/white) ADSR and AR envelopes, a triangle and square wave LFO, and a sample-and-hold function. The later Version III model had a variable expression keyboard allowing flattening or sharpening of the pitch and the addition of vibrato depending on key pressure and position.4Mark Vail, (2000), Vintage Synthesizers: Pioneering Designers, Groundbreaking Instruments, Collecting Tips, Mutants of Technology, 2000 by Backbeat Books.

ARP 2800 Odyssey Mki
ARP 2800 Odyssey MkI

ARP Production model timeline 1969-1981:

    • 1969 – ARP 2002 Almost identical to the ARP 2500, except that the upper switch matrix had 10 buses instead of 20.
    • 1970 – ARP 2500
    • 1970 – ARP Soloist (small, portable, monophonic preset, aftertouch sensitive synthesizer)
    • 1971 – ARP 2600
    • 1972 – ARP Odyssey
    • 1972 – ARP Pro Soloist (small, portable, monophonic preset, aftertouch sensitive synthesizer – updated version of Soloist)
    • 1974 – ARP String Ensemble (polyphonic string voice keyboard manufactured by Solina)
    • 1974 – ARP Explorer (small, portable, monophonic preset, programmable sounds)
    • 1975 – ARP Little Brother (monophonic expander module)
    • 1975 – ARP Omni (polyphonic string synthesiser )
    • 1975 – ARP Axxe (pre-patched single oscillator analog synthesiser)
    • 1975 – ARP String Synthesiser (a combination of the String Ensemble and the Explorer)
    • 1977 – ARP Pro/DGX (small, portable, monophonic preset, aftertouch sensitive synthesiser – updated version of Pro Soloist)
    • 1977 – ARP Omni-2 (polyphonic string synthesiser with rudimentary polyphonic synthesiser functions – updated version of Omni)
    • 1977 – ARP Avatar (an Odyssey module fitted with a guitar pitch controller)
    • 1978 – ARP Quadra (4 microprocessor-controlled analog synthesisers in one)
    • 1979 – ARP Sequencer (analog music sequencer)
    • 1979 – ARP Quartet (polyphonic orchestral synthesiser not manufacted by ARP – just bought in from Siel and rebadged )
    • 1980 – ARP Solus (pre-patched analog monophonic synthesiser)
    • 1981 – ARP Chroma (microprocessor controlled analog polyphonic synthesiser – sold to CBS/Rhodes when ARP closed)

The demise of ARP Instruments was brought about by disorganised management and the decision to invest heavily in a guitar style synthesiser, the ARP Avatar. Although this was an innovative and groundbreaking instrument it failed to sell and ARP were never able to recoup the development costs. ARP filed for bankruptcy in 1981.5and fall of ARP instruments’ By Craig R. Waters with Jim Aikin


  • 1
    Trevor Pinch, Frank Trocco, (2004) Analog Days: The Invention and Impact of the Moog Synthesizer, Harvard University Press.
  • 2
    Peter Forrest, (1994) The A-Z of Analogue Synthesizers, Susurreal Publishing, Devon, England
  • 3
    ARP 2600 Promotional material 1971
  • 4
    Mark Vail, (2000), Vintage Synthesizers: Pioneering Designers, Groundbreaking Instruments, Collecting Tips, Mutants of Technology, 2000 by Backbeat Books.
  • 5
    and fall of ARP instruments’ By Craig R. Waters with Jim Aikin

The ‘Allen Computer Organ’, Ralph Deutsch – Allen Organ Co, USA, 1971

Allen Computer Organ of 1971
Allen 301-3 Digital Computer organ of 1971

The Allen Computer Organ was one of the first commercial digital instruments, developed by Rockwell International (US military technology company) and built by the Allen Organ Co in 1971. The organ used an early form of digital sampling allowing the user to chose pre-set voices or edit and store sounds using an IBM style punch-card system.

The Rockwell/Allen Computer Organ engineering  team with a prototype model.
The Rockwell/Allen Computer Organ engineering team with a prototype model.

The sound itself was generated from MOS (Metal Oxide Silicon) boards. Each MOS board contained 22 LSI (Large Scale Integration) circuit boards (miniaturised photo-etched silicon boards containing thousands of transistors – based on technology developed by Rockwell International for the NASA space missions of the early 70’s) giving a total of 48,000 transistors; unheard of power for the 1970’s.

Publicity photograph demonstrating  the punch-car reader
Publicity photograph demonstrating the punch-car reader
Allen Organ voice data punch cards
Allen Organ voice data punch cards
Allen Computer Organ
Allen Computer Organ


The ‘Triadex Muse’ Edward Fredkin & Marvin Minsky, USA, 1971

Triadex Muse
The Triadex Muse

The Triadex Muse was an idiosyncratic sequencer based synthesiser produced in 1972. Designed by Edward Fredkin and the cognitive scientist Marvin Minsky at MIT, the Muse used a deterministic event generator that powered by early digital integrated circuits to generate an audio output. The Muse was not intended as a musical instrument per-se but as a compositional tool (as well as an artificial intelligence experiment), therefore the audio output was left purposefully simple; a monophonic square-wave bleep. The Muse was designed to be connected to a number of other Triadex units  –  an Amplifier and speaker module, a Multi-Muse Cable (used to link multiple Muses together), and a Light Show module; a colour sequencer whose 4 coloured lamps blink in time to the Muse’s signals, using Triadex’s own proprietary standard (therefore they were unable to connect to any other voltage controlled instrument)

Triadex Muse and Amplifier/Speaker module
Triadex Muse and Amplifier/Speaker module

The Muse had no keyboard control but a series of eight slider each with forty set positions. Four of the sliders controlled the interval between notes, and the other four controlled the overall sequence ‘theme’. Visual feedback was provided by a series of displays next to the sliders showing the status of the logic gates. Another set of sliders control the volume from the internal speaker, the tempo of the sequence, and the pitch. Additional switches allow you to start the sequence from the beginning, step through it note-by-note, or substitute a rest point in place of the lowest note.




‘GROOVE Systems’, Max Mathews & Richard Moore, USA 1970

Max Mathews with the GROOVE system
Max Mathews with the GROOVE system

“GROOVE is a hybrid system that interposes a digital computer between a human composer-performer and an electronic sound synthesizer. All of the manual actions of the human being are monitored by the computer and stored in its disk memory ”

Max Mathews and Richard Moore 1 Joel Chadabe, Electric Sound: The Past and Promise of Electronic Music, Prentice Hall, 1997.p158

In 1967 the composer and musician Richard Moore began a collaboration with Max Mathews at Bell Labs exploring performance and  expression in computer music in a ‘musician-friendly’ environment. The result of this was a digital-analogue hybrid system called GROOVE  (Generated Realtime Operations On Voltage-controlled Equipment) in which a musician played an external analogue synthesiser and a computer monitored and stored the performer’s manipulations of the interface; playing notes, turning knobs and so-on. 2Joel Chadabe, Electric Sound: The Past and Promise of Electronic Music, Prentice Hall, 1997.p158The objective being to build a real-time musical performance tool by concentrating the computers limited power, using it to store musical parameters of an external device rather than generating the sound itself :

“Computer performance of music was born in 1957 when an IBM 704 in NYC played a 17 second composition on the Music I program which I wrote. The timbres and notes were not inspiring, but the technical breakthrough is still reverberating. Music I led me to Music II through V.  A host of others wrote Music 10, Music 360, Music 15, Csound and Cmix. Many exciting pieces are now performed digitally. The IBM 704 and its siblings were strictly studio machines–they were far too slow to synthesize music in real-time. Chowning’s FM algorithms and the advent of fast, inexpensive, digital chips made real-time possible, and equally important, made it affordable.”  3Max Mathews. “Horizons in Computer Music,” March 8-9, 1997, Indiana University.

Richard Moore with the Groove System
Richard Moore with the Groove System

The system, written in assembler, only ran on the Honeywell DDP224 computer that Bell had acquired specifically for sound research. The addition of a disk storage device meant that it was also possible to create libraries of programming routines so that users could create their own customised logic patterns for automation or composition. GROOVE allowed users to continually adjust and ‘mix’ different actions in real time, review sections or an entire piece and then re-run the composition from stored data. Music by Bach and Bartok were performed with the GROOVE at the first demonstration at a conference on Music and Technology in Stockholm organized by UNESCO  in 1970. Among the participants also several leading figures in electronic music such as Pierre Schaffer and Jean-Claude Risset.

“Starting with the Groove program in 1970, my interests have focused on live performance and what a computer can do to aid a performer. I made a controller, the radio-baton, plus a program, the conductor program, to provide new ways for interpreting and performing traditional scores. In addition to contemporary composers, these proved attractive to soloists as a way of playing orchestral accompaniments. Singers often prefer to play their own accompaniments. Recently I have added improvisational options which make it easy to write compositional algorithms. These can involve precomposed sequences, random functions, and live performance gestures. The algorithms are written in the C language. We have taught a course in this area to Stanford undergraduates for two years. To our happy surprise, the students liked learning and using C. Primarily I believe it gives them a feeling of complete power to command the computer to do anything it is capable of doing.” 4 Max Mathews. “Horizons in Computer Music,” March 8-9, 1997, Indiana University.

The GROOVE System at the Bell Laboratories circa 1970
The GROOVE System at the Bell Laboratories circa 1970

The GROOVE system consisted of:

  • 14 DAC control lines scanned every 100th/second ( twelve 8-bit and two 12-bit)
  • An ADC coupled to a multiplexer for the conversion of seven voltage signal: four generated by the same knobs and three generated by 3-dimensional movement of a joystick controller;
  • Two speakers for audio sound output;
  • A special keyboard to interface with the knobs to generate On/Off signals
  • A teletype keyboard for data input
  • A CDC-9432 disk storage;
  • A tape recorder for data backup

Antecedents to the GROOVE included similar projects such as PIPER, developed by James Gabura and Gustav Ciamaga at the University of Toronto, and a system proposed but never completed by Lejaren Hiller and James Beauchamp at the University of Illinois . GROOVE was however, the first widely used computer music system that allowed composers and performers the ability to work in real-time. The GROOVE project ended in 1980 due to both the high cost of the system – some $20,000, and also  to advances in affordable computing power that allowed synthesisers and performance systems to work together flawlessly. 5 F. Richard Moore, Elements of Computer Music, PTR Prentice Hall, 1990.


  • 1
    Joel Chadabe, Electric Sound: The Past and Promise of Electronic Music, Prentice Hall, 1997.p158
  • 2
    Joel Chadabe, Electric Sound: The Past and Promise of Electronic Music, Prentice Hall, 1997.p158
  • 3
    Max Mathews. “Horizons in Computer Music,” March 8-9, 1997, Indiana University.
  • 4
    Max Mathews. “Horizons in Computer Music,” March 8-9, 1997, Indiana University.
  • 5
    F. Richard Moore, Elements of Computer Music, PTR Prentice Hall, 1990.