OPL (Operator Type-L) is an FM synthesis sound system used for MSX-AUDIO. The chip was designed and manufactured by Yamaha. The chip reference used for the MSX-AUDIO is Y8950.

There is also another OPL referenced YM3526 that not have ADPCM recording and playback capability. It is not used for MSX-AUDIO.

Note that it is also called OPL1 by some people.