It uses a synthesizer, which looks a lot like an electronic keyboard, but its function and internal structure are very different.

Crystal music generally means that the timbre of crystal is used in it. The timbre of crystal is the 99th timbre in the MIDI standard. It is actually a sound synthesized by a synthesizer, that is to say, a sound made artificially through the synthesis of waveforms. However, the sound is as clear as crystal, so it is named crystal. Generally, electronic keyboards may have crystal timbres, but the timbre is far less beautiful than that produced by professional synthesizers