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RMI | Harmonic Synthesizer


The RMI Harmonic Synthesizer sounds as wild and wonderful as it looks. Having 2 sets of 16 harmonic draw-bars allows one to rapidly create extraordinary tones in stereo - separate oscillators for left and right channels. Wide-ranging vibrato/tremolo effects, noise modulation, pitchbend, portamento, four octave ranges, oscillator sync, arpeggiator, pedal-controlled filter are just some of the versatile functions provided, most of them independently for each oscillator. 

From the RMI Product Brochure

The Harmonic Synthesizer - a precise approach to synthesis. You are given accurate control of waveforms by Digital harmonic Generators - 2 digital oscillators with 16 sliders for producing harmonics 1x to 16x. At your command are relative intensities of all overtones to beyond audibility! Each of the two digital harmonic generators produce an independent audio output for exotic contrasts in stereo. Preset waveforms can be selected or mixed with the generators for instant changes. Dynamic effects are created by voltage-controlled filters with low-pass, bandpass, and high-pass mixable outputs. Intricate melodic and rhythmic sequencer patterns are created by holding chords. Digital circuitry insures tuning stability and drift-free performance. The controls are rugged. The case is tough. RMI enjoys a history of building trouble-free instruments.

1974-76 Mark: RMI (Rocky Mount Instruments inc. USA). 

Low Pass, Band pass, High pass (Left Channel Only). Modulations: VCF sweeps (sweep up, sweep down, time and via LFO) - also by optional filter pedal. 

SEQUENCER (Arpeggiator)
Percussion patterns or melodic lines will be played as long as chords are held. Sequences can arpeggiate from bottom to top or random. 

Left and right Harmonic Generators provide independent audio outputs for feed to musical instrument amplifiers. 

16 heavy duty slide pots adjust the intensities of the fundamental frequency and overtones to beyond audibility, allowing precise waveform control. A manual low-pass filter provides further coloration. Playing range can be moved 4 octaves by the Octave Shifter. Tuning is adjusted (over more than one octave range) by a slider. Output level is controlled by a slider. Final volume can be foot-controlled. Outputs from the Harmonic Generator or any of the 5 preset waveforms (clarinet, pulse, flute, horn, reed) can be selected or mixed using coloured illuminated pushbuttons. 

Frequency and/or amplitude modulation of the Harmonic Generators by any of the 4 waveforms is controllable in rate and degree. Noise modulation of frequency is available. Pitch Bend provides further frequency deviation upon attack of the note - time and depth are variable. Portamento is activated for both generators by a long touch bar immediately above the keyboard. Portamento speeds can be controlled independently for each generator. 

Low-pass, bandpass and high-pass outputs are mixable. Resonance is variable. Controls include envelope generator, LFO, sine and optional foot pedal. The left generator only can be routed through the filter. 

A tough black vinyl case houses the synthesizer. The keyboard and controls are enclosed by a cover for travel. Dimensions - 9.5 inches high x 42.5 inches wide x 23.5 inches deep. Four heavy chrome steel legs unfold from the bottom of the keyboard, adding 26.5 inches to the height. Weight: 37kg Includes custom filter pedal, keyboard cover, folding legs, copy of manual and tuning/alignment guide.
ModelHarmonic Synthesizer
Engine TypeAnalog
Voices (max)1
LFO2 Saw Up, Saw Down, Sine, Square
Engine Detailed2 DCO, 16 harmonics (phase-locked) per OSC, one for left and 1 for right. 5 preset waveforms: Clarinet, Flute, Pulse, Horn, Reed.
Filter (VCF)1 24dB Slope (4-pole), Band Pass, Low Pass, Resonance, left channel only (OSC 1)
Envelope (VCA)Normal mode, AD, Percussion mode, Decay only
ArpeggiatorAs long chord is pressed: Up, Down, Random
Key typeKeys
AudioStereo out, mono in
CV-gateCV in
Extra infoBetween 150 and 250 made
Produced:1974 - 1976
Legend: Obvious Y: Yes, N: No, N/A: Not Applicable
VCO Voltage Controlled Oscillator DCO Digital Controlled Oscillator
LFO Low Frequency Oscillator Sub Sub Oscillator
VCF Voltage Controlled Filter VCA Voltage Controlled Amplifier
Velocity As with a piano, the harder you hit a key, the louder the sound, unlike most organs which always produce the same loudness no matter how hard you hit a key. Aftertouch Pressing a key after you activated it. Channel Aftertouch, no matter which key, it will send a Channel message. Poly Aftertouch, sends the pressure per key instead of the whole channel.
Values for OSC, LFO, Filter, Envelope are per voice unless stated otherwise.

Manuals, patches etc.


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