by Robin Vincent | Approximate reading time: 2 Minutes

JPS Harmonic Synthesizer  ·  Source:

RMI Harmonic Synthesizer  ·  Source:


The RMI Harmonic Synthesizer was the first synth to use digital technology for sound generation. It first arrived in 1974, nine years before the Yamaha DX-7 which is regarded as the start of the digital age of synthesis. It’s a funny looking device – like an electric organ crashed into a Moog. Now the new JPS Harmonic Synthesizer rack extension for Reason aims to resurrect its legenadary sounds.


Rocky Mountain Instruments (RMI) were part of the Allen Organ Company. The style of the instrument is amazing, almost a cliché of vintageness, even down to the funky font on some of the labelling. Before the Harmonic Synthesizer then produced the Electra-piano favoured by Genesis, Yes and Deep Purple and then somehow managed to release a digital sample player that used waveform models on punch cards – and this was the early 70’s! The RMI Harmonic Synthesizer featured two digital harmonic generators with 16 harmonics each, an LFO, arpeggiator, VCF with mixable LP, BP and HP outputs, and AM and FM capability. It can be heard on Jean Michel Jarre’s Oxygéne album and plays the bass and lead on the title track.

So how does this recreation stack up? On first inspection they have certainly captured the look of the synth control panel. I particularly like the way the preset buttons are all slightly off kilter. They’ve added a few controls to the panel; mod and pitch wheels; pan knob; and they’ve expanded the envelope sections, but otherwise it fits the profile. Few virtual synth makers can resist the urge to embellish upon the focus of their development and so despite the painstakingly “modelled logarithmic resister potentiometers” they couldn’t help themselves in adding things like another preset per oscillator, panning and a polyphonic gated mode to the arpeggiator. They’ve also added a bunch of stomp box effects called the Acidman FX Array. All this is good stuff and helps bring the potential out of this ancient box of sounds.


In listening to the sound examples I feel the JPS Harmonic Synthesizer sits somewhere on the edge between gritty 80’s synth and a Bontempi keyboard but somehow manages to sound interesting rather than naff. There’s some unusual character here that, if you’re a Reason user, would be worth checking out.

JPS Harmonic Synthesizer is available now as a Reason Rack Extension for €79 from the Propellerheads website.

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