The Yamaha DX21 is a digital synthesizer that emerged in the 1980s, part of Yamaha's renowned DX series. Featuring Frequency Modulation (FM) synthesis technology, the DX21 offers a distinctive sonic palette with crystalline tones, powerful bass, and ethereal pads. Its 61-key keyboard and user-friendly interface appealed to many musicians, and its versatility made it a favored choice for music production of the time. The DX21 continues to be appreciated for its unique sonic character and its impact on the music of the 1980s.