MS-34 Digital Complex Sound Generator

MS-34 is a three-tone, one noise, monophonic chip synthesizer. Direct control over each oscillator’s frequency and output level make it an ideal building block in modulator designs. It is based on one of the earliest sound chips capable of producing all the frequencies needed to accurately hit the notes used in Western music. While the square wave generators may not be considered “complex” by today’s standards, it was revolutionary for its time.

The three square wave oscillators are modeled to include voltage slew and drop. This gives a little extra edge to its nostalgia evoking tones.

The linear feedback shift register (LFSR) noise generator has a very unique sound not present in modern noise generators. The frequency of the noise period can be adjusted to three preset values, or it can clocked to the rate of the third tone generator. Selecting the rate via CV input allows for triggering of different percussive sounds.

When the MS-34 is added to the rack it accept notes from a sequencer lane just like any other instrument. Its main note and gate CV inputs are also very traditional in their function. The oscillators can be detuned from one another like any other multi-oscillator synthesizer.

The real power comes from driving the individual voices and noise generator with their dedicated CV inputs. This is how the people who wrote video game music back in the 1980s would have treated the chip. Each voice acting as its own instrument, sometimes playing off each other to form chords, other times going in different directions to play leads and basslines. In direct control mode, the gate function more like voltage controlled amplifiers. They are not strictly on/off gates, but can be varied up and down while a note is sounding for tremolo volume effects. The note and pitch inputs work the same way, and can be altered at any time while the gate is open for vibrato, or dramatic slides.

While the chip that offered inspiration for the MS-34 was not stereo, some of the later systems to use it sent each voice’s output to an external stereo mixer chip. Separate outputs for each voice and noise allow the same application to be realized. Simply connect each output to its own mixer channel and use the pan provided there.

One last note. Because of how at home MS-34 is being part of a modular synthesis system, many of the included examples make use of Rack Extension from other developers. These are clearly noted in the patch names. Not to worry, there are also plenty of examples that only use factory devices. Enough to give you some ideas of what is possible, and get you on your way to building your own modular projects.