Lesson Summary 

Define the role of the VCO in a synthesizer and describe the historical importance using specific song examples


The synthesizer can be traced back to the early 19th century.  American inventor Thaddeus Cahill invented theTelharmonium in 1897.  This predecessor weighed in at 200 tons and powered by a steam engine. The telharmoniumwas in fact polyphonic, was used in several concerts in which music was played through the  public telephone network in 1906.

Russian inventor Leon Theremin created the monophonic instrument that shares his namesake.  Theremin stumbled upon this discovery while working on Russian spy technology in the 1920's.  The instrument works without the player ever making direct contact.  The Theremin electronically determines the proximity of the player’s hands within an electrostatic field.  Two antennae are used to measure distance to control both pitch and volume.  The Theremin was featured heavily in early Sci-Fi soundtracks including the The Day the Earth Stood Still and the original Dr. Whotelevision series. At 19 years old American inventor and founder of Moog Music, R. A. (Bob) Moog, began his first business by building and selling Theremin kits. It is this reason that Moog Music still builds and sells Theremin kits to this day. 

Before the 1950’s all precursors to the modern-day synthesizer were based on tube circuitry making them unreliable and expensive. After the transistor became available more viable instruments were created. It was in 1963 that Bob Moog created the first successful voltage controlled oscillator and amplifier with a keyboard.  His collaboration with German composer Herbert Deutsch pushed Moog to expand the range of his modules, however it was not until 1967 that Moog actually described his instruments as synthesizers.  It was in the following year, 1968, that Wendy Carlos’ LP “Switched-On Bach” became the first commercial success utilizing the Moog analog synthesizer. The album’s success introduced the synthesizer to an international audience and made the name Moog synonymous with the synthesizer. By the 1970’s the Moog synthesizer had been adopted and featured by Stevie Wonder, The Beach Boys, Keith Emerson, Pink Floyd, and The Beatles.  Today Moog’s iconic sounds can be heard through all genres of music from Lady Gaga, Nine Inch Nails, Kanye West, and Radiohead. 



Oscillation - A repetitive variation in time of a measurement around a point of equilibrium.  Common examples include electrical sound production (VCO), mass-spring systems, crystal oscillators, and alternating current. 

Voltage Controlled Oscillator (VCO) - An oscillator that is controlled by an external voltage.   The Werkstatt includes a VCO with both a Pulse wave and Sawtooth wave output.  This oscillator is the main tone generator to be sent on to other parts of the Werkstatt for wave shaping. 


Listen to the included audio files in this lesson.  These run a wide range in terms of genre and era but one this is constant, the use of Moog synthesizers.  Kraftwerk is one of the first electronic musical acts in the 1970's and laid the foundation for modern day EDM.  Stevie Wonder's "Boogie on Reggae Woman" is one of the earliest examples of the Moog bass sound. This use of the Moog bass sound changed the way funk and soul were presented all throughout the 70's and into the modern era. Additionally, James Burke and Passion Pit are examples of modern day representatives of the Moog sound.    


Jumper Cables


Our first exercise with the Werkstatt will involve changing the frequency of the tone produced.  Match the Werkstatt settings to those in Figure 1.  


  Figure 1. VCO Sweep setting.


Now as a class everyone slowly turn the FREQ knob clockwise.  The frequency of the Werkstatt has a range from around 8 Hz to 16 kHz.  As you turn the FREQ knob you should hear something like a rocket ship taking off.  If you had matched the settings in Figure 1 you would have completed a Saw wave sweep, switch the WAVE setting to PULSE and complete another frequency sweep.  How do these two sounds differ from each other? 

Match the settings in Figure 2 to experiment with the VCO MOD settings.  This section of the Werkstatt allows the player to assign different modulation control over the way the VCO sounds.  


 Figure 2. VCO MOD settings


Experiment with the LFO RATE and VCO MOD AMOUNT knobs.  How do these change the sound and why?