MUSYS. Peter Grogono, United Kingdom, 1969

EMS was the London electronic music studio founded and run by Peter Zinovieff in 1965 to research and produce experimental electronic music. The studio was based around two DEC PDP8 minicomputers, purportedly the first privately owned computers in the world.

One of the DEC PDP8 mini-computers at EMS
One of the DEC PDP8 mini-computers at EMS

Digital signal processing was way beyond the capabilities of the 600,000 instructions-per-second, 12k RAM, DEC PDP8s; instead, Peter Grogono was tasked with developing a new musical composition and ‘sequencing’ language called MUSYS. MUSYS was designed to be an easy to use, ‘composer friendly’ and efficient (i.e. it could run within the limitations of the PDP8 and save all the data files to disk – rather than paper tape) programming language to make electronic music.  MUSYS, written in assembly language, allowed the PDP8s to control a bank of 64 filters which could be used either as resonant oscillators to output sine waves, or in reverse, to read and store frequency data from a sound source. This meant that MUSYS was a type of low resolution frequency sampler; it could ‘sample’ audio frequency data at 20 samples per second and then reproduce that sampled data back in ‘oscillator mode’. MUSYS was therefore a hybrid digital-analogue performance controller similar to Max Mathew’s GROOVE System (1970) and  Gabura & Ciamaga’s PIPER system (1965) and a precursor to more modern MIDI software applications.

“It all started in 1969, when I was working at Electronic Music Studios (EMS) in Putney, S.W. London, UK. I was asked to design a programming language with two constraints. The first constraint was that the language should be intelligible to the musicians who would use it for composing electronic music. The second constraint was that it had to run on a DEC PDP8/L with 4K 12-bit words of memory.”

The two PDP8’s were named after Zinovieff’s children Sofka (an older a PDP8/S) and Leo (a newer, faster a PDP8/L). Sofka was used as a sequencer that passed the time-events to the audio hardware (the 64 filter-oscillators,  six amplifiers, three digital/analog converters, three “integrators” (devices that generated voltages that varied linearly with time), twelve audio switches, six DC switches, and a 4-track Ampex tape-deck). Leo was used to compute the ‘score’ and pass on the data when requested by Sofka every millisecond or so;

“These devices could be controlled by a low-bandwidth data stream. For example, a single note could be specified by: pitch, waveform, amplitude, filtering, attack rate, sustain rate, and decay time. Some of these parameters, such as filtering, would often be constant during a musical phrase, and would be transmitted only once. Some notes might require more parameters, to specify a more complicated envelope, for instance. But, for most purposes, a hundred or so events per second, with a time precision of about 1 msec, is usually sufficient. (These requirements are somewhat similar to the MIDI interface which, of course, did not exist in 1970.)”



Previous to the development of MUSYS, the EMS PDP8s were used for the first ever unaccompanied performance of live computer music ‘Partita for Unattended Computer’ at Queen Elizabeth Hall, London, 1967. Notable compositions based on the MUSYS sytem include: ‘Medusa’ Harrison Birtwistle 1970, ‘Poems of Wallace Stevens’  Justin Connolly. 1970, ‘Tesserae 4’  Justin Connolly 1971, ‘Chronometer’  Harrison Birtwistle 1972, ‘Dreamtime’ David Rowland 1972, ‘Violin Concerto’  Hans Werner Henze 1972.

Audio Examples

Demonstrating the digital manipulation of a voice with the frequency sampler:

In the Beginning‘ PeterGrogono with Stan Van Der Beek 1972. “In 1972, Stan Van Der Beek visited EMS. Peter Zinovieff was away and, after listening to some of the things we could do, Stan left with brief instructions for a 15 minute piece that would “suggest the sounds of creation and end with the words ‘in the beginning was the word'”. All of the sounds in this piece are derived from these six words, heard at the end, manipulated by the EMS computer-controlled filter bank.”

Datafield‘ Peter Grogono 1970

Chimebars  Peter Grogono 1968

 MUSYS code examples

A composition consisting of a single note might look like this:

      #NOTE 56, 12, 15;

The note has pitch 56 ( from an eight-octave chromatic scale with notes numbered from 0 to 63), loudness 12 (on a logarithmic scale from 0 to 15), and duration 15/100 = 0.15 seconds. The loudness value also determines the envelope of the note.

An example of a MUSYS  program that would play fifty random tone rows:

      50 (N = 0 X = 0
      1  M=12^  K=1  M-1 [ M (K = K*2) ]
         X & K[G1]
         X = X+K  N = N+1  #NOTE M, 15^, 10^>3;
         12 - N[G1]

MUSYS evolved in 1978 into the MOUSE programming language; a small, efficient stack based interpreter.


Peter Grogono.’MUSYS: Software for an Electronic Music Studio. Software – Practice and Experience’, vol. 3, pages 369-383, 1973.

EMS Synthesisers, Peter Zinovieff, Tristram Cary, David Cockerell United Kingdom, 1969

EMS (Electronic Music Studios) was founded in 1965 by Peter Zinovieff, the son of an aristocrat Russian émigré with a passion for electronic music who set up the studio in the back garden of his home in Putney, London. The EMS studio was the hub of activity for electronic music in the UK during the late sixties and seventies with composers such as Harrison Birtwistle, Tristram Cary, Karlheinz Stockhausen and Hans Werner Henze as well as the commercial electronic production group ‘Unit Delta Plus  (Zinovieff, Delia Derbyshire and Brian Hodgson).

Front panel of the DEC PDP8i
Front panel of the DEC PDP8i

Zinovieff , with David Cockerell and Peter Grogono developed a software program called MUSYS (which evolved into the current MOUSE audio synthesis programming language) to run on two DEC PDP8 mini-computers allowing the voltage control of multiple analogue synthesis parameters via a digital punch-paper control.  In the mid 1960’s access outside the academic or military establishment to, not one but two, 12-bit computers with 1K memory and a video monitor for purely musical use was completely unheard of:

” I was lucky in those days to have a rich wife and so we sold her tiarra and we swapped it for a computer. And this was the first computer in the world in a private house.” – Peter Zinovieff

The specific focus of EMS was to work with digital audio analysis and manipulation or as Zinovieff puts it “ To be able to analyse a sound; put it into sensible musical form on a computer; to be able to manipulate that form and re-create it in a musical way” (Zinovieff 2007). Digital signal processing was way beyond the capabilities of the DEC PDP8’s; instead they were used to control a bank of 64 oscillators (actually resonant filters that could be used as sine wave generators) modified for digital control. MUSYS was therefore a hybrid digital-analogue performance controller similar to Max Mathew’s GROOVE System (1970) and  Gabura & Ciamaga’s PIPER system (1965).

Peter Zinovieff at the controls of the PDP8 Computer, EMS studio London
Peter Zinovieff at the controls of the PDP8 Computer, EMS studio London

EMS studio diagram (from Mark Vail’s ‘ Vintage Synthesizers’)

Even for the wealthy Peter Zinovieff, running EMS privately was phenomenally expensive and he soon found himself running into financial difficulties. The VCS range of synthesisers was launched In 1969 after Zinovieff received little interest when he offered to donate the Studio to the nation (in a letter to ‘The Times’ newspaper). It was decided that the only way EMS could be saved was to create a commercial, miniaturised version of the studio as a modular, affordable synthesiser for the education market. The first version of the synthesiser designed by David Cockerell, was an early prototype called the  Voltage Controlled Studio 1; a two oscillator instrument built into a wooden rack unit – built for the Australian composer Don Banks for £50 after a lengthy pub conversation:

“We made one little box for the Australian composer Don Banks, which we called the VCS1…and we made two of those…it was a thing the size of a shoebox with lots of knobs, oscillators, filter, not voltage controlled. Maybe a ring modulator, and envelope modulator” David Cockerell 2002

vcs-3_0001 The VCS1 was soon followed by a more commercially viable design; The Voltage Controlled Studio 3 (VCS3), with circuitry by David Cockerell, case design by Tistram Cary and with input from Zimovieff . This device was designed as a small, modular, portable but powerful and versatile electronic music studio – rather than electronic instrument – and as such initially came without a standard keyboard attached. The price of the instrument was kept as low as possible – about £330 (1971) – by using cheap army surplus electronic components:

“A lot of the design was dictated by really silly things like what surplus stuff I could buy in Lisle Street [Army-surplus junk shops in Lisle Street, Soho,London]…For instance, those slow motion dials for the oscillator, that was bought on Lisle street, in fact nearly all the components were bought on Lisle street…being an impoverished amateur, I was always conscious of making things cheap. I saw the way Moog did it [referring to Moog’s ladder filter] but I adapted that and changed that…he had a ladder based on ground-base transistors and I changed it to using simple diodes…to make it cheaper. transistors were twenty pence and diodes were tuppence!” David Cockerell from ‘Analog Days’

Despite this low budget approach, the success of the VCS3 was due to it’s portability and flexibility. This was the first affordable modular synthesiser that could easily be carried around and used live as a performance instrument. As well as an electronic instrument in it’s own right, the VCS3 could also be used as an effects generator and a signal processor, allowing musicians to manipulate external sounds such as guitars and voice.

VCS3 with DK1 keyboard
VCS3 with DK1 keyboard

The VCS3 was equipped with two audio oscillators of varying frequency, producing sine and sawtooth and square waveforms which could be coloured and shaped by filters, a ring modulator, a low frequency oscillator, a noise generator,  a spring reverb and envelope generators. The device could be controlled by two unique components whose design was dictated by what could be found in Lisle street junk shops; a large two dimensional joystick (from a remote control aircraft kit) and a 16 by 16 pin board allowing the user to patch all the modules without the clutter of patch cables.

The iconic 16 X 16 pin-patch panel of the VCS3
The iconic 16 X 16 pin-patch panel of the VCS3. The 2700 ohm resistors soldered inside the pin vary in tolerance 5% variance and later 1%; the pins have different colours: the ‘red’ pins have 1% tolerance and the ‘white’ have 5% while the ‘green’ pins are attenuating pins having a resistance of 68,000 ohms giving differing results when constructing a patch.

The original design intended as a music box for electronic music composition – in the same vein as Buchla’s Electronic Music Box – was quickly modified with the addition of a standard keyboard that allowed tempered pitch control over the monophonic VCS3. This brought the VCS3 to the attention of rock and pop musicians who either couldn’t afford the huge modular Moog systems (the VCS3 appeared a year before the Minimoog was launched in the USA) or couldn’t find Moog, ARP or Buchla instruments on the British market. Despite it’s reputation as being hopeless as a melodic instrument due to it’s oscillators inherent instability the VCS3 was enthusiastically championed by many british rock acts of the era; Pink Floyd, Brian Eno (who made the external audio processing ability of the instruments part of his signature sound in the early 70’s), Robert Fripp, Hawkwind (the eponymous ‘Silver Machine‘), The Who, Gong and Jean Michel Jarre amongst many others. The VCS3 was used as the basis for a number of other instrument designs by EMS including an ultra-portable A/AK/AKS (1972) ; a VCS3 housed in a plastic carrying case with a built-in analogue sequencer, the Synthi HiFli guitar synthesiser (1973), EMS Spectron Video Synthesiser, Synthi E (a cut-down VCS3 for educational purposes) and AMS Polysynthi as well as several sequencer and vocoder units and the large modular EMS Synthi 100 (1971).

Despite initial success – at one point Robert Moog offered a struggling Moog Music to EMS for $100,000 – The EMS company succumbed to competition from large established international instrument manufacturers who brought out cheaper, more commercial, stable and simpler electronic instruments; the trend in synthesisers has moved away from modular user-patched instruments to simpler, preset performance keyboards. EMS finally closed in 1979 after a long period of decline. The EMS name was sold to Datanomics in Dorset UK and more recently a previous employee Robin Wood, acquired the rights to the EMS name in 1997 and restarted small scale production of the EMS range to the original specifications.

Peter Zinovieff.  Currently working as a librettist and composer of electronic music in Scotland.

David Cockerell, chief designer of the VCS and Synthi range of instruments left EMS in 1972 to join Electro-Harmonix and designed most of their effect pedals. He went to IRCAM, Paris in 1976 for six months, and then returned to Electro-Harmonix . Cockerell  designed the entire Akai sampler range to date, some in collaboration with Chris Huggett (the Wasp & OSCar designer) and Tim Orr.

Tristram Cary , Director of EMS until 1973. Left to become Professor of Electronic Music at the Royal College of Music and later Professor of Music at the University of Adelade. Now retired.

Peter Grogono Main software designer of MUSYS. Left EMS in 1973 but continued working on the MUSYS programming language and further developed it into the Mouse language. Currently Professor at the Department of Computer Science, Concordia University, Canada.

The Synthi 100 at IPEM Studios Netherlands.
The Synthi 100 at IPEM Studios Netherlands.

The EMS Synthi 100

The EMS Synthi 100 was a large and very expensive (£6,500 in 1971)  modular system, fewer than forty units were built and sold. The Synthi 100 was essentially  3 VCS3’s combined; delivering a total of 12 oscillators, two duophonic keyboards giving four note ‘polyphony’ plus a 3 track 256 step digital sequencer. The instrument also came with optional modules including a Vocoder 500 and an interface to connect to a visual interface via a PDP8 computer known as the ‘Computer Synthi’.  

Images of EMS Synthesisers


VCS3 Manual (pdf)

Sources: ‘Analog Days’. T. J PINCH, Frank Trocco. Harvard University Press, 2004

‘Vintage Synthesizers’: Pioneering Designers, Groundbreaking Instruments, Collecting Tips, Mutants of Technology. Mark Vail. March 15th 2000. Backbeat Books

Peter Forrest, The A-Z of Analogue Synthesisers Part One A-M, Oct 1998.