Vintage Digital Synthesizer 1977

June 16, 2015 · Posted in Uncategorized

The Bell Labs Digital Synthesizer, better known as the Alles Machine or Alice, was an experimental additive synthesizer designed by Hal Alles at Bell Labs during the 1970s. The Alles Machine used 72 computer controlled oscillators whose output was mixed to produce a number of discrete “voices” for output. The Alles Machine has been called the first true digital additive synthesizer,following on earlier Bell experiments that were partially or wholly implemented as software on large computers. Only one full-length composition was recorded for the machine, before it was disassembled and donated to Oberlin Conservatory’s TIMARA department in 1981. Several commercial synthesizers based on the Alles design were released during the 1980s, including the Atari AMY sound chip.

This 1977 tape is one of the earliest examples of purely digital realtime audio synthesis. It manages to achieve an analog synth sounding quality, but it is entirely digital synthesis and signal processing.

The interactive software I wrote and am playing in this video recycles my keyboard input into an accompaniment to my continued playing, which is why I called it a “concerto generator”. I use part of one of the keyboards for control data entry, and the small switches upper right to access pre-entered numerical patterns. The sliders are mainly pre-Yamaha FM synthesis parameter controls, for the number of harmonics and amplitude and frequency of the FM modulator and carrier that constituted each musical voice.