Oberheim OB-Mx

Oberheim OB-Mx Image

The OBMx is a modern synthesizer module with an audio path that is entirely analog. It has an intuitive and powerful interface which makes it easy for anyone to program their own unique sounds. The OBMx claims to deliver the classic Oberheim and Minimoog sounds while being completely programmable and midi compatible.

One historical point is that the OB-Mx is, at present, the last synthesizer designed by Don Buchla. Buchla has sort of disowned this unit, though. Its filters are actually pretty bad. They don't manage to emulate either the 2-pole Oberheim or 4-pole Moog filters In fact they sound notoriously thin and tweezy. The so-called 'Oberheim filter' provides 12 dB/oct low, band or hi pass filtering, with resonance. And the 'Minimoog filter' uses a meatier 24 dB/oct low-pass filter.

The OB-Mx was one of the few real analog synths, however, available with completely modern features. And because it comes from Oberheim, you can expect great sounds, design, and features. The OB-Mx is highly user upgradeable. Out of the box the OB-Mx comes with one two voice expansion card which contains the two oscillators, 4 multistage envelopes, 3 LFO's, and filters. Up to 6 of these cards can be easily installed sufficiently adding to the phattness of this synth and its capabilities. Unfortunately, the high cost of extra voice cards also made a fully-outfitted OB-Mx a very pricey proposition when put up against other more commonly-available digital instruments of its time. It has been used by Nine Inch Nails, Sneaker Pimps, Apollo 440, DJ Spinna, and U2.

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11 Visitor comments
April 11, 2014 @ 7:38 pm
No, thats true. To get the full filter potential you will have to work with ex. ENV4 with a 100% sustain, that you matrix modulate to -0.50 ca to get the filter to close even more. Then you can matrix modulate ENV1 once again for higher sweep. And if you set ENV3 to a really fast decay (0.1) you can matrix-add a little extra spike to the sound, giving it a really hard edge.

Its a great synth, but I guess that many reviewers only tried the on panel knobs. Without Matrix-routing its really just half a synth. But once you start fiddling with the matrix in combo with the filters… Oh'boy..
December 20, 2011 @ 1:34 am
Got a 4-voice. For me it seems you cannot get full envelope filter sweep by just using the ENV to +1.00 in the filter section, I have to also add a matrix modulation patch with a multiplier set to +0.83 or something to get it to sweep from fully open to fully closed with an envelope. I had the envelope amplitude set to max. Is this true or am I missing something?
December 20, 2011 @ 1:24 am
You should have all the preset sounds at patch number 192 and upwards
0-191 will be empty after a battery replacement
December 13, 2011 @ 11:24 pm
Does anyone know how to get the factory presets back. I had mine worked on and all the presets are gone and I'd like to get them back.
November 11, 2011 @ 7:38 am
this synthesizer is wonderful. i love it more than any synth i've ever tried.

here a better demonstration:

VSE Rating


User Rating

Rated 3.79 (220 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Specifications
  • Polyphony - 2 voice (expandable to 12)
  • Oscillators - 2 per voice; Triangle, Sawtooth, Pulse Width waveforms
  • LFO - 3 LFOs (triangle, sawtooth, sample/hold)
  • Filter - 2 filters per voice; Resonant 12 dB/oct Oberheim type filter with low, band, hi pass and a 24 dB/oct Minimoog low-pass filter section
  • VCA - 4 multistage envelopes per voice
  • Keyboard - None
  • Memory - 256 patches, 256 performances
  • Control - MIDI (12 parts)
  • Date Produced - 1994
  • Resources & Credits
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