Article History

63% MelonadeM

ym2151 (format)

Yamaha OPM / YM2151

Point Type:
File Types:
Max Filesize:
The Yamaha YM2151, also known as OPM, is an eight-channel, four-operator sound chip. YM2151 only, no expansion chips!
  1. Tools
  2. Restrictions on submit
  3. Playback (for voting)
  4. See also
The Yamaha YM2151, also known as the OPM Chip (Operator Type M), is a sound chip that uses FM synthesis for sound generation. It was notably used in a number of arcade system boards as well as the Sharp X68000 home computer.

It features 8 FM channels, with 4 operators each. Very similar to the YM2612 used in the Sega Genesis, but lacking SSG-EG. It also gains a coarser detune setting (DT2), a wider variety of options for LFO (broader speed range, and with a varying number of waveforms), and an AY/YM PSG style noise generator, usable on Channel 8's 4th operator.


DefleMask Tracker (set to Arcade system, but do not use SP channels for legal entries)
Furnace Tracker (can set to YM2151 only)
XPMCK (the CPS1 system supports both the YM2151 and the OKIM6295, but please use the YM2151 only!)

Restrictions on submit

Your submission should only use one YM2151 chip. Not two, and certainly no other soundchips whatsoever. If you want to add more, consider submitting to the wildchip or VGM format.

Open questions:
  • Should formats other than .vgm be allowed (e.g. .mdx/.pdx for Sharp X68000)
  • Do we cap the chip clock rate between 3 MHz and 4 MHz? 3.58MHz seemed to be common for a lot of arcade titles, and 4MHz is what the X68000 uses. Furnace allows the user to toggle between these two settings.

Playback (for voting)

Use vgmplay or the latest in_vgm plugin Winamp for .vgm files. You should make sure to set the emulation core to NukedOPM, if possible.

See also