Yamaha YM2612

[1] The YM2612 removes the SSG component (although retaining its envelope generators) and GPIO ports found in the YM2203 and YM2608,[1] which were elements of the integrated YM2149F core on the other OPN chips.

Any output that is sufficiently low in volume undergoes an exaggerated quantization, including any usage of fades in video game music.

Also, because of the reduced dynamic range of the built-in DAC, additional distortion may be generated when playing sounds with a very high volume.

[1] In recent years, improvements in accuracy of the emulation of the sound chips resulted in the low volume distortion bug in the YM2612 being faithfully replicated in software, and many recent Mega Drive/Genesis emulators since have offered this feature as an option to replicate the sound outputs of the original and revised models of the Mega Drive/Genesis.

This version has an improved built-in DAC that significantly reduces the presence of crossover distortion from the original chip with a higher signal-to-noise ratio than the YM2612.

Used in conjunction with the Texas Instruments SN76489 PSG as the main sound generators of the Sega Mega Drive/Genesis console, the YM2612 was prominently utilized by numerous prolific video game music composers, most notably Yuzo Koshiro.

Yamaha YM2612
An example of the low volume distortion created by the peculiar qualities of the YM2612's built-in DAC. This sample is from the Mega Drive game Beyond Oasis .
In some cases, this low volume distortion can affect the loudness, and to some degree the timbres, of certain sounds. This sample is from the Mega Drive game Streets of Rage 2 .