adlib refers to either to certain FM synthesis chips that use either the YM3812 (OPL2) or the YMF262 (OPL3) chips, as well as derivatives produced by Yamaha and others. The Adlib name comes from the fact that the original chips where produced by Ad Lib Co., but their chips lacked a PCM feature, so they were outcompeted by the SoundBlaster chip, which had all the features of the original AdLib chips, but also had PCM. The YM3812 had support for 9 channels of 2OP fm, and the YMF262 had support for 18 channels of 2OP fm, as well as options for drum channels and up to 6 4OP instruments. A derivative produced by ESS technology, the ESFM, allowed for 20 channels and more than 6 4OP instruments, but there were no trackers developed that used this chip.

See also