Synth Programing – Korg MS20 Lesson 1

Synth Programing – The Oscillators

In the following video Jose Gross – Course Leader at The Recording Workshop UK in London explains the function of the oscillators or VCOs on the classic Korg MS20 monophonic synthesizer.

Synth Programing - Korg MS20The Korg MS20 is a classic analog synthesizer dating back to around 1976 and is a great way to learn synth programing as its layout is easy to follow.

The oscillators are the waveform generators which create the basic or raw sound we hear and the Korg MS20 features two of them called VCO1 and VCO2, VCO standing for voltage controlled oscillator – the higher the voltage the higher the pitch . They can produce Sawtooth, Triangular or Square waves. To add extra richness VCO 1 has an additional control called a pulse width control that modifies the shape of the square wave, as demonstrated in the video, which adds more ‘richness’ to the tone by altering the harmonic content. This is often used to create those so called ‘fat’ synth sounds. There is also a white noise generator that produces every frequency from 20Hz to 20KHZ giving us that ‘hissy’ kind of sound often used to produce wind, rain or the sound of the sea. Together with various modifiers it also makes up some of the percussive effects found in snare drums and hi hats in electronic drum sounds.

Each oscillator also features a scale control that lets you to alter the pitch, and these are calibrated in feet, relating to the actual size of pipes found in a church organ, ranging from 2′ on VCO2 all the way down to a deep 32′ pipe on VCO1.

VCO2 differs slightly from VCO1 in that it does not have a pulse width control, however it does have a ring modulation feature. Ring modulation is where the amplitude of one wave is modulated by the other, similar to AM radio, and this produces a ‘bell’ influence to the sound as Jose Gross demonstrates in the video. This 2nd oscillator has a pitch control enabling you to tune the oscillator relative to VCO1. Ever so slightly detuning it gives you a very rich sound and is often used in synth programing as part of that fat sound creation as mentioned above.

The output of each oscillator then goes into a mixer where you can adjust the level of each one, which lets you further modify the overall tonal quality of the resulting sound.

Portmento is a control that enables a gliding effect between two notes, typically used from one note to an octave below or above, often used in dance tracks.

Synth Programing can be very confusing and seem complicated to the newcomer especially if using software synthesizers and on the synth programing course you start of by learning how to use hardware, getting your hands on the actual synth demonstrated by Jose, moving onto other hardware synthesizers, then onto soft synths, gaining both practical and theoretical knowledge on how synthesizers work and how to use them.

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