Oberheim Matrix 6R
6 Voices Polyphonic Module (1986)

 

Module rackmount version of the Matrix 6 synthesizer.

The Matrix series gets the name the Digital Matrix Control a complex signal modulation router. First model was the classic Matrix 12 synthesizer, today quite sought-after.

RACKMOUNT 2 units - the main panel features a 16-characters VDF fluorescent display (adjustable brightness), 23 membrane buttons and 1 volume slider.

Rear panel terminal connectors:
- main out ( 2 sounds can be split left and right)
- cassette interface I/O
- Midi interface
- expression pedal input (cutoff / volume / assignable to the matrix)
- pedalswitch input for sustain or analog trigger input
- memory protect switch
- headphones (front)
- remote connector (front) for custom Sysex editor, a prototype never released.

 

 

VOICE main core based on a 8-bits Motorola 6809 CPU manages 6 channels polyphony.
Each voice is composed by 2 (quite) identical DCO oscillators based on 6 X CEM 3396 IC (big body version). Below an oscillator table sum-up

 

	DCO1	DCO2
waveforms	pulse / saw / wave / both*	pulse / saw / wave / noise / both*
rect. width	yes	yes
sync	yes 1>2 (3 modes)	no
detune	no	yes
volume gain	yes (mix 1/2)	yes (mix 1/2)
key click sound	yes	yes

* range value is from 0 to 63: 0 is the sawtooth, 63 the triangle. Middle values are combo mixes of saw/triangle (waveshaping)

 

PERFORMANCE a LOT of useful functions;
- bender lever can be assigned to pitch DCO1 / DCO2 / both
- modulation lever can be assigned to LFO / VCF cutoff
- 3 modes portamento generator (for pitch or cutoff)
- keyboard split in 2 zones "LOWER" and "UPPER"
- voice split / dual modes: 2+4 / 4+2 / 6+0 / 0+6 ("0" to splillover data by Midi)
- unison stack mode (6 voices, no detune)
- master tune (also autotune function)
- key velocity to VCF / LFO
- 3 voices rotate modes
- 3 keyboard response curves : linear + 2 exponential
- calibration mode for DOC and VCF

FILTER the system take advantage of the Curtis 3396 from the DCO which includes a 4 poles resonant filter. The VCF can auto-oscillate and consequently modulate the DCO1 by Frequency Modulation process. It follows the FM basic principle like Yamaha DX-7 but in this case the DCO1 is the modulator and the VCF is the carrier.

ENVELOPE 3 EGs (4 segments + 1 delay time + 1 main level)
1- EG1 is assigned into the matrix control
2- EG2 is routed to amplitude by default but can be re-assigned by matrix control
3- EG3 is be assigned into the matrix control
The 3 EGs are triggered in 4 modes: retrigger, free flown, reset. lfo + external signal.
In addition 2 RAMP GENERATORS: a kind of EG-triggers with only attack portion which can be defined using the RATE parameter. Finally 2 dynamic VCA controllers (linear or exponential) also generated by the Curtis IC.

LFO there are basically 2 modulators (shapes: sawtooth up / down, triangle, square, random, S&H and noise) with variable depth, 3 retrig modes and lag mode.
1- LFO1 : destinations can be freely assigned into the matrix modulation
2- LFO2 : destinations can be freely assigned into the matrix modulation
A third slimmed-down LFO3 acts as a simple vibrato with individual depth, frequency and same shapes.

MATRIX the computerized section is a kind of signal router previously implemented in more expensive Matrix 12: a totally open structure! each sound manages up to 10 combinations between 20 sources and 32 destinations (see table below)
TRAKING GENERATOR function tracks and transform one of the 20 modulation matrix sources (the INPUT) through 5 defined points, then the final shaped result is the OUTPUT. Each tracking point has 63 different values and can be smoothed using a lag process.

Sources: Destinations: EG 1 / 2 / 3 LFO 1 / 2 vibrato ramp generator EG 1 / 2 velocity aftertouch pedal 1 / 2 modulation lever (bipolar) pitch lever (bipolar) keyboard velocity / aftertouch pitch DCO1 / DCO2 pulse width DCO1 / DCO2 waveshape DCO1 / DCO2 filter cutoff filter resonance EG1 delay /attack / decay / release / amp EG2 delay /attack / decay / release / amp LFO1 frequency / depth LFO2 frequency / depth portamento speed DCO1 / DCO2 balancing FM amount

 

MIDI basic contro changes, but full sysex implementation. Some controls:
- program change
- pedals and levers can be CC# re-assigned
- it is possible to assign 2 Midi channel to lower and upper part (bitimbric).

MEMORY
- 100 patch slots
- 50 split zones configurations (the "multis")
Sounds can be saved to Midi exclusives dump or by tape.
Battery replacement: CR-2032 in battery holder, easy to replace.

 

 

EDITOR here's a selection of both free and commercial Matrix 6R editors:
- Midiquest (PC/MAC, commercial)
- DR.T Matrix editor (ATARI ST screenshot)
- M1000X (MAC , free)
- Synlib (free)
- Oberheim Matrix Patch Editor (FREE, max MSP)
- Ctrlr editor (free)
- Obiex401 (free, DOS old PC)
- Patch Touch (IOS, commercial)

 

 

RELATED FAMILY:

	MATRIX 6 keyboard version, same characteristics
	MATRIX 1000 hyper compressed Matrix6 technology keeping similar structure but different board. Interface is even more limited and deep edit is not possible from panel. Considered more as a "preset" matrix with no less than 1000 sounds on board. Matrix 6 and 1000 are compatible. Also a later "white face" version VIDEO
	MATRIX 12 the Matrix concept started with this classic huge expensive synthesizer with impressive finish and many more tweaks VIDEO
	ACCESS MATRIX PROGRAMMER same concept as the MICROWAVE PROGRAMMER Sadly it features a limited edit (no matrix access) and it can be replaced by any computer editor - check out list below VIDEO

 

VST PLUGIN / SAMPLED VERSION there is NO official Matrix 6R VST plugin emulator.
Here is a selection of free samples sources and related plugins:

	name	price	link	demo
	OPX PRO II	Commercial VST. Classic Oberheim sound from 70
	waveformless	FREE samples		n/a
	Logic-caffe	FREE samples		n/a
	kontakt banks	-commercial -free demo		n/a

AUDIO DEMO

Ultima IV* game theme - all matrix 6 polished Missing polyphony!

hammond organ (quite) resonance brassy

*Ultima IV is a game by Origin, music by Kenneth. W. Arnold WIKI-LINK

Soundcloud Oberheim Matrix 6R

VIDEO CLIP SELECTION Demo demo2 demo3