Roland Jupiter-4

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Jupiter-4 by Roland
Synthesis type:		Analog Subtractive
Polyphony:		4 voices
Timbrality:		Monotimbral
Oscillators:		1 VCO + 1 sub-oscillator per voice
Filter:		1 resonant lowpass, 1 highpass
Attenuator:		2 ADSR
LFO:		1 triangle/square/sawtooth/reverse sawtooth
Velocity sensitive:		No
Aftertouch:		No
External control:		None
Memory:		10 presets/8 user patches
Onboard effects:		chorus
Produced:		1978 - 1981
Original price:		Approx. US$2000

The Roland Jupiter 4 was an analog synthesizer manufactured by the Roland Corporation of Japan between 1978 and 1981. It was notable as the company's first self-contained polyphonic synthesizer, and for containing digital control of analog circuits (termed "Compuphonic" by Roland), allowing for such features as programmable memories and voice assignment modes.

Priced at around US$2,000, it was cheaper than polyphonic machine from its competitors (such as the Sequential Circuits Prophet-5 and the Oberheim OB-X) however it did not sell well in comparison. (These poor fortunes were reversed on the release of its successor model in 1981, the popular Jupiter-8.)

The Jupiter 4's basic architecture was 4 identical voice cards, each with a VCO (with sub-oscillator), resonant low pass VCF (which could self-oscillate), and VCA. Modulation included an ADSR envelope and LFO. The LFO, routable to oscillator pitch, pulse width, filter cutoff and amplifier, was notable for being able to reach audio frequencies, allowing for crude FM and AM synthesis.

The Jupiter 4's two most distinctive features were provided by virtue of its "compuphonic" digital control of the four voice cards:

An arpeggiator, with a choice of up, down, up/down, or random mode. The arpeggiator can be prominently heard in Duran Duran's 1982 hit single "Rio."
Four voice assignment modes, which, as well as simple 1VCO-per-voice polyphony, included the ability to effect 4-VCO unison when one key was pressed, 2-VCOs per voice when two keys were pressed, and 1-VCO per voice when three or four keys were pressed. This effect can be heard on tracks such as "Seconds" by The Human League and "I Dream of Wires" by Gary Numan.

The final signal path also included a simple high pass filter and a stereo chorus effect. The Jupiter 4 had 10 preset sounds and also featured 8 memory locations for user-created patches.

Despite not being incredibly popular, it did manage to find its way into the hands of some musicians, most of which were associated with the New Wave and synthpop music scenes (see below). Phil Oakey of The Human League eulogised that despite its limitations "the Jupiter 4 will be tatooed on my heart for ever".

[edit] Promars

In 1979, Roland released a monophonic version of the Jupiter-4 called the Promars. The Promars did not have the arpeggiator and the chorus effect, but introduced a second oscillator. It had the memory and preset selection buttons above the keyboard, which were less clumsy to use than those on the Jupiter-4. It also had 37 keys, making slightly smaller than the Jupiter-4.

The Promars was used by Depeche Mode (around early-mid 1982), Vangelis (early/mid 1980s), The Enid, Jethro Tull, Landscape and Spandau Ballet (synth lead on 'To Cut a Long Story Short').