The instrument
The SAS-20 was Korg's first attempt at a personal keyboard with a versatile accompaniment section. It has 12 polyphonic sounds that can be modified with a stereo chorus. A built-in computer analyzes the melody played on the keyboard and generates an accompaniment. Korg thus presented the world's first automatic accompaniment function of this kind to be built into a keyboard. The keyboard has 61 keys, 19 for the accompaniment on the bottom row and 42 for the melody on the top row.
Details
The accompaniment section of the SAS-20 has mixer controls for percussion, bass and chords as well as a movable tempo control. There are 12 programmed voices: Piano, Strings, Organ, Flute, Electric Piano, Vibraphone, Harpsichord, Brass Ensemble, Jazz Organ, Clarinet, Guitar, Clav Synthe. The 16 rhythms of the auto-accompaniment are: Beat 1 - 3, Ballad 1 and 2, Rock 1 - 4, Country, Bossa Nova, Shuffle, Disco, Bluegrass, Latin, Rhythm & Blues and Jazz. The effects are melody chord, sustain and stereo rhythm. There is a chorus and faders for drums and bass lines. Rhythm, bass and arpeggios are mixable.