Sunday, August 7th, 2022 09:24 am
The Matrix-12, truly one of the "Monsters" of programmable analog synthesizers. It is
basically two complete Oberheim Xpanders hooked up to a velocity-sensitive (including
release velocity), pressure-sensitive (there were some early Matrix-12s that did not
have pressure-sensitivity), 5-octave, 61-note (C-C) keyboard. With 24 oscillators (two
VCOs per voice) it can be set up as a 12-part monophonic or a 6-part polyphonic multi-
timbral synth. The front panel is exactly like the Xpander, except for one button that
switches between voices 1-6 and 7-12.
Like the Xpander, each voice consists of 2 VCOs (triangle, saw, pulse, or noise, VCO2
could be synced to VCO1), a multimode VCF (low-pass, band-pass, notch-pass, high-
pass and four "combination" filter modes), and 4 VCA's (in line one after each oscillator
and two after the VCF). FM of VCO1 and the VCF is possible via VCO1. The filters can
also be set as 1-pole (6dB/octave), 2-pole (12dB/octave), 3-pole (18dB/octave), or 4-
pole (24dB/octave). All oscillators and filters can be tuned by a handy auto-tuned
routine. In addition to this basic synth engine, the Matrix-12 has a number of separate
modules that can be inserted in any modulation path. These include (10) LFO's with
basic waves plus sample-and-hold and random functions, 6 tracking generators, 6 ramp
generators, two lag processors (they do not necessarily have to be used for
portamento), and 1 additional global LFO to be used with the Mod Wheel.
Unlike the Xpander, the Matrix-12 does not have individual outputs (although they were
available as an option, which involved replacing a side panel to make room for the
connectors) or CV/gate inputs.
"The intention with the Matrix-12 was to offer, in a mid-1980's context, an instrument
that had the routing flexibilty of the giant modular systems of the mid-1970's, wherein
almost every parameter could interact using patch cords. The Matrix-12's "patch cords,"
of course, are hidden in software.
"It's an impressive-looking instrument, large to the point of bulkiness, with an
exceptionally deep main panel awash with buttons and LEDs, like some sort of space-
age board game. But it's not the system that's so radical on the Matrix-12 -- after all, it's
fairly standard subtractive synthesis -- so much as the options offered.
"Beknobbed to an extent, the Matrix-12 is navigated with a page system of parameter
access and soft buttons. Such a method may now be commonplace, but in 1985, it was
new and not a little confusing.
"The instrument has 12 fully independent analog voices. Within a few years, what would
become known as multitimbralism was also commonplace. Back in 1985, many of us
nodded sagely at the prospect of being able to control individual voices on dedicated
MIDI channels, but few thought many people would ever want to bother. In truth, the
Matrix's system does not have the multitimbral flexibility of an 01/W, but for independent
bass, pad and obligato parts, say, it is still more than sufficient.
"There's nothing too frightening about the VCO/VCF/VCA voice architecture. More
daunting is the level of choice within each section. Each oscillator can be independently
pitched, fine-tuned and set in volume. Page 2 of the oscillator controls provides access
to waveforms -- triangle, sawtooth or variable pulse -- as well as the lag processor for
portamento effects, pitch bend and vibrato. VCO2 also offers noise as an additional
"The oscillator pages are reasonably fathomable, but once you get into the filter pages,
where a choice of some 15 filter modes and the myriad modulation routings (with no
less than five envelope generators per voice, five LFOs and a ramp generator) confront
you, then you'll need your wits about you. Oberheim breezily informs you that some 27
modulation sources can be sent out to some 47 modulation destinations.
"Filtering is a Matrix-12 specialty, with spectacular choices of one-, two-, three- or four-
pole lowpass; one-, two- or three-pole highpass; two- or four-pole bandpass; band
reject; phase shift; and several combined filter types. Add in tricks like being able to
modulate filter resonance from keyboard dynamics, one of the LFOs, etc., and you can
see that this is never going to be a quick or easy instrument to work with, in spite ot the
plethora of Help pages and a clearly written and organized owner's manual.
"Does it sound any good once you have mastered it? Yes, it definitely does. The Matrix-
12 is a rich, multifaceted instrument, capable of enormous complexity and fine detail,
perfectly suited for progressive noodlings a la Alan Holdsworth, who has loyally used
the Matirx-12 and Xpander as a sound source for his Synthaxe guitar. This application
as a sound source for a guitar controller makes perfect use of the Matrix-12's
multitimbral capability for individual string bending sounds, etc. Texture hounds like The
Orb also seem to have taken the Matrix-12 into the hearts.
"This is a synth with a thousand tricks up its software. It wasn't made in huge numbers,
but since it is not for the fainthearted, most people on the lookout for a Matrix-12 should
be rewarded in time. Though official production stopped far earlier, a small number of
Matrix-12s were made to order by the "new" Oberheim in 1991."
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