The instrument
The D-20 is a 9-fold multi-timbral, 32-voice digital synthesiser with 61 velocity-sensitive keys and MIDI. 8 tonally playable parts and a rhythm part make use of LA synthesis, the combination of PCM samples without filter and simple synthesis but with filter. The predecessor was the D-50, the D-10 and the D-110 rack module appeared at the same time, followed somewhat later by the D-5 and D-70. The D-20 is effectively a D-10 with an additional sequencer and floppy disc drive. A PG-10 programmer can be connected for easier programming. The D-20 and the other models in the D series were the first synthesisers to have demo songs in ROM.
Details
The sound programme of the D-20 is called ‘Timbre’ and is made up of 2 ‘Tones’, which in turn are made up of one or 2 ‘Partials’. A partial is either a PCM oscillator (ROM samples) with a downstream amp or a pulse-width modulated oscillator (triangle/rectangle) with a dynamic filter and amp. 13 structures can be selected for the combination of the two partials to form a tone, so that a sound programme can consist of up to 4 oscillators. The filter offers resonance without self-oscillation and sounds extremely ‘warm’.
The internally available 256 PCM samples are slightly shorter than on the first LA synthesiser D-50. The sound generation is the same as on the D-5, D-10 and D-110 and ends with a digital reverb that offers 8 algorithms. The D-20 has a built-in drum computer that can be used to put together a song from 1 to 2 bar patterns or to play the sounds manually in manual mode. There are 32 preset and 32 freely programmable patterns. The D-20 has Performance and Multitimbral modes. 128 Performances, 64 Tones and 64 Timbres can be stored internally, an inserted M-128 or M-256 memory card doubles the memory. (Source: Rolandmuseum)