Skidmore College

FM History

Dr. John Chowning

John Chowning (you are hearing his composition "Phone") was the first to discover Frequency Modulation (FM) synthesis. While radio engineers had known for years that FM radio produced various ”Sidebands”, or spectral components of the carrier material (the music that is broadcast ov er the air waves), the modulation of those frequencies was far above the range of human hearing. Chowning discovered that by bringing the modulation rate down into the range of human hearing ( 20Hz – 20,000 Hz), and by using a computer to strictly control the relationship between the carrier frequency [Fc], the modulating frequency[Fm], and the amount of modulation (delta f), interesting, useful and even predictable musical timbres would result.

Frequency modulation synthesis also turned out to be a much less computationally intense process that simple additive synthesis, where sine tones are stacked up to create artificial spectral recipes (musical tone colors).

In the early stages of Chownings’ work, he had great difficulty convincing American manufacturers of the value of his discovery and so it was Yamaha corporation of Japan which first realized the tremendous potential of his new invention.

This lead to the creation of many powerful commercial synthesizers which were readily affordable for the general public. Chowning’s work has been used by thousands of computer music composers and even more popular music composers in the form of Yamaha’s “DX” and “TX” series of synthesizers (i.e. DX7, DX7-IIFD, DX-21, TX-802 and SY77).


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