ABSTRACT
Early commercial keyboard synthesizers were analog designs using transistor circuits for the audio oscillators that create the musical notes and for the various modulators and filters that process the sounds from the oscillators. Type of analog-style digital synthesizer is programmed entirely in software that runs either as a stand-alone computer program or as a plug-in. The Hammond organ was arguably the first commercial additive synthesizer, though acoustic pipe organs have been around for many centuries. A synthesizer whose tone can be varied by control voltages can be programmed to perform similar changes over time, adding warmth and a human quality to musical notes created entirely by a machine. An oscillator in a synthesizer is the electronic equivalent of strings on a guitar or piano. One important way synthesizer players add interest is by varying the sound quality of notes over their duration. Modern synthesizers are very sophisticated, and most include tons of great preset patches programmed by professional sound designers.
