The instrument
The Yamaha DX-21 is a 61-key synthesiser based on FM synthesis. It is 8-voice polyphonic. A simplified version of the DX7, it is an entry-level keyboard with no velocity or aftertouch sensitivity.
Details
The DX21 uses digital FM synthesis to generate sound using four operators, two combinations with a sine wave generator and an envelope generator, and eight algorithms. There are 128 pre-programmed voices in the internal ROM memory. These are organised in groups of eight and can be loaded individually or in groups into the 32-voice RAM memory. There is also a 32-voice RAM performance memory and controls for pitch bend wheel, modulation wheel, volume, balance and data entry. Three playing styles are possible: single, dual and split. A built-in cassette interface allows for programming and storage of an unlimited number of voices that can be loaded into RAM memory. The DX21 has a wide range of MIDI functions.