Kurzweil originally developed reading machines for the blind but later adapted some of the same technologies to music systems.

In 1984 they released their first instrument, the K250, which was considered to be the first really successful attempt at emulating the sound of a grand piano.

The company's flagship line of synthesizers, the K2xxx series began with the K2000 released in 1990, which introduced the V.A.S.T. (Variable Architecture Synthesis Technology) engine and became very popular during the 1990s in top recording studios and for use with music production for film.

Later models included the K2500 (1996) (shown), the K2600 (1999) and the K2661 (2004), but all were discontinued in 2008. This leaves only the PC3, introduced in 2008, which has next-generation VAST technology but no sampling capability.