Yamaha · 1985 · 1980s–1990s · 9 voices
The OPL2 and OPL3 FM synthesis chips powered PC gaming audio from the late 1980s through the mid-1990s, and their two-operator FM sound — capable of both grating bleeps and surprisingly musical tones — defined a generation of DOS game soundtracks.
The Yamaha YM3812 (OPL2) was a 9-channel FM synthesis chip with 2-operator synthesis per voice and four waveforms, first popularised by the AdLib card (1987) and then by Creative Labs' Sound Blaster family. The YMF262 (OPL3) doubled the channel count to 18 in OPL2 mode (or 15 in extended mode) and added four additional waveforms and a stereo output with four panning positions. Two-operator FM synthesis produced a more limited timbral palette than the 4-operator chips used in arcade and console hardware, but resourceful composers created recognisable instruments by carefully tuning operator ratios and envelope shapes. The OPL2/3 became the universal standard for PC game audio because Creative Labs built the chips into the Sound Blaster line, which won the compatibility war; games from 1989 to 1995 were expected to support AdLib/Sound Blaster as the minimum audio target. Bobby Prince's Doom soundtrack and Robert Prince's id Software scores exploited OPL2 particularly effectively.