Oberheim have been one of the big names in the synthesiser world for the past 15 years. Whilst having built up a reputation for having very powerful and unique sounding instruments, they are also known for being rather expensive. Last year, the biggest news to come from Oberheim was the arrival of their 'Xpander'. This is certainly the most powerful MIDI expander to date, as it has one of the most elaborate modulation sections of any analogue synthesiser, as well as a full complement of sophisticated features making its two VCO configuration extremely powerful.

Oberheim's latest synthesiser, the Matrix 12, is essentially two Xpanders controlled by a velocity sensitive keyboard which can be split into six overlapping sections, giving a total of twelve voices - each capable of having a different voice and MIDI channel at the same time.

OVER THE TOP?

One of the most impressive features of the Xpander, and therefore the Matrix, is in the immense control offered by the modulation section. A single Xpander gives you a choice of 27 modulation sources within every voice, each of which can be sent to any of 47 modulation destinations. These sources can also go to many destinations at one time with positive or negative individual control of each destination. What this amounts to is a truly versatile system, the equivalent of which had until now only been found on large modular synthesiser systems costing tens of thousands of pounds.

Each of the Matrix's 12 voices gives you no less than two oscillators, with Sawtooth, Triangle and variable Pulse waveforms; a 15-mode filter; two output amplifiers in series with programmable stereo panning; five envelope generators each with Delay, Attack, Decay, Sustain, Release and its own output amplifier; five Low Frequency Oscillators, each with Triangle, Square, Up and Down Sawtooths, Random and Noise waveforms, with sampling (sample/hold) of any modulation source; four Ramp Generators with programmable ramp rate; three Tracking generators that can change the scaling or shape of a modulation source; a Lag Processor for Portamento effects between any modulation source and destination; and FM VCA for frequency modulation of either VCO1 or the filter by VCO2.

This may appear a little excessive for a synth which hopes to conquer the mass market, however the Matrix is no ordinary synthesiser, and it carries no ordinary price tag. To justify its retail price Oberheim's 'angle' is that with the Matrix you can get the equivalent of several more conventional synthesisers from the one box. This is achieved by the very complex patching of the keyboard assignment and voices, called Multipatch Programming.

LAND OF THE MULTIPATCH

The Matrix has 100 voice memories, called Single Patches. Each Single Patch stores all the parameters as well as the name of the patch. Then there are the 100 Multipatches which will store combinations of Single Patches (the 12 voices being able to have a different Single Patch each), MIDI channel selection, panning, volume, transposition and detune for each voice.

Up to six 'keyboards' can be had on the Matrix at the same time, and these are also remembered by the Multipatches. They can be configured into Split, Double, Triple, Quadruple, etc, even from an external MIDI controller without split capabilities!

The Matrix is very straightforward and accessable in relation to other similarly complex systems too. Its front panel is very similar to that of the Xpander - 120 characters of fluorescent alphanumeric display from the two display windows. The actual front panel is divided into five areas - Master, Programmer, Modulation/Source select, Page Modifier and Single/Multipatch Page Select. These are the means with which all the various features are accessed, with the data entry either being achieved by numeric entry from the keypad, or from the six knobs beneath the displays.

The Master section is the simplest of the sections to master (I refuse to apologise for the unintentional pun...), as it accesses all the non-programmable parameters which will affect all facets of the instrument - master volume, master tuning, auto-tuning, MIDI channels, cassette save/load etc. Although there are only three buttons in the master section, the multifunctions are accessed through use of 'pages'. Therefore, by pressing the Master Page button the displays indicate the new functions of the 12 buttons and six knobs beneath the two central displays so then the buttons relate to function switching, and the knobs relate to data entry. In this way, all of the hundreds of different functions that the Matrix possesses can be accessed and controlled from very few buttons.

The primary controls for sound synthesis are accessed from the Single/Multi Patch Page Selectors, which are located on the right hand side of the front panel. Along with having flow chart diagrams of the signal path, these assign the control knobs to the VCO1, VCO2, VCF/VCA, Envelope Generator, FM VCA and Lag Processor, LFO Primary parameters, keyboard Tracking Generator, and Ramp parameters.

To run-through these features in detail might prove a little tiresome for you impatient readers; however, this synthesiser's modulation section deserves a closer look as it is unique.

TO MODULATE OR NOT?

As I mentioned earlier, there are no less than 27 modulation sources within every one of the Matrix's 12 voices each of which can be sent to any of the 47 modulation destinations within the voices.

There are modulation sources and destinations in every stage of the signal generation - in the VCO1 you can have frequency modulation, Pulse Width Modulation, and Volume Modulation. In the VCF you can have frequency modulation of the cutoff point, resonance amplitude, and separate amplitude modulation of the two VCAs. A rather unique destination for modulation is in the envelope generator where you can modulate each of its five stages individually as well as its VCA. The speed and amplitude of the LFO itself can be modulated, the FM amplitude can be modulated as can the Lag processor's rate, along with each of the six keyboard tracking points and Ramp rate!

What is even more astounding is that the modulation routing is designed so that they can all modulate each other - Envelope 5 can control the amplitude of LFO1 which in turn might be assigned to modulate the Pulse Width of VCO2. Such a configuration might seem completely unreasonable and beyond the bounds of usefulness, but this example is a very viable one as it will result in a chorusing effect as well as an apparent drop in octave while the note is sustaining...

Keeping track of all the different locations of modulation activity would normally become a bit tricky with so many possibilities, and therefore a feature has been added to the Matrix (which is not found on the Xpander) which enables viewing of all the modulations of a particular voice as a list, showing the modulation source and destination, and the modulation amount for each of these busses.

THE SOUNDS

As each of the 12 voices can be a different sound, or simply have different variations of a basic patch (for example a slightly different pitch modulation rate, detuning etc.), in theory the sounds which the Matrix should be capable of producing should be 'Huge'. Indeed there are many factory programs which demonstrate the unique power within the Matrix very well, although these sounds are rather unconventional. The more useable and conventional sounds however, (such as pianos, strings and brass) are rather disappointing for such a complex synthesiser. However the Matrix is undoubtedly an elusive beast to tame, these sounds might well not be representative of its true potential. (For a full breakdown of the sounds listen to the cassette demo).

The keyboard itself has quite a comfortable feel to it, being light, responsive, and easy to play. At the time of writing, the keyboard was only velocity sensing, though I am reliably informed that it will soon be modified to be after-touch sensing too.

The construction of the Matrix appears to be fairly sturdy as well as being light enough to be easily transportable. There are very few protrusions to be broken off, and whilst on the subject of protrusions, the modulation 'wheels' are still of the rather uninspiring Oberheim 'flip-flop' variety.

The Matrix's rear panel has a lot less sockets than are found on the Xpander - no CV/Gate Ins, and no individual outputs. It simply has the mixed outputs - Left, Right and Mono, a Trigger Input, Cassette and MIDI ports, Memory Protect switch, Footpedal sockets, and Footswitch socket for chain advance. The patches themselves can be chained, and therefore advanced through the chain either by the footswitch, or by a MIDI sequencer. It is a shame though that there aren't individual outputs for each of the 12 voices as being able to have different voices for each note makes the Matrix a very useful sound generator for a sequencer, giving many individual voices for monophonic sequencer lines in addition to polyphonic sequences. This, I feel, makes the omission of individual outputs a bit restricting in a professional studio environment.

CONCLUSION

The Matrix-12 is undoubtedly a very powerful and expressive instrument. It is, for such a complex machine, relatively easy to get on with, and as with most American musical products its instruction manual is a joy to read and learn from. It not only delves into the depths of this particular instrument, but also into the depths of synthesis and modulation.

Price: £4598.85
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