This page was last modified 14:37, 25 July 2023 by Gdx. Based on work by Iamweasel2 and Mars2000you and others.



OPL4 is a FM sound synthesiser with the Yamaha YMF278B, YMF704 (OPL4-ML) or YMF721 (OPL4-ML2) sound chip. Only the YMF278B is used on the MSX system.

It is paired with a YAC513 companion floating-point DAC chip or an alternative compatible DAC chip.

It is an upgraded version of the OPL3. Although not officially part of the standard, it has been adopted by the MSX scene, especially in Europe.

OPL4 cartridges

The Sunrise MoonSound was the original, but many other compatible clones have been made since, such as


All clones can hold 1 MB of Sample-RAM and have the 2 MB Yamaha YRW801-M General MIDI ROM on board.

However, technically the OPL4 can address 4 MB Sample-RAM if no 2 MB Yamaha ROM is present, which is a feature that’s offered by the DalSoRi R2.

Wozblaster Enhanced offers the 2 MB Yamaha YRW801-M General MIDI ROM on board and 2 MB of Sample-RAM.


Three different chips are used as DAC:

According to the JunSoft and Tecnobytes manufacturers, the Philips and Sanyo chips provide better sound quality and low noise.


The FM part of the OPL4 part began being supported by the MSX-AUDIO BIOS since v1.3, including stereo sound. The DalSoRi R2 by JunSoft has a FlashROM for the BIOS.


The DalSoRi, DalSoRi R2, FM Blaster, MSX-Blaster OPL4, OPL4 Shockwave 2 and Wozblaster Enhanced are the smallest and fit in a Konami sized cartridge.

The Wozblaster is larger and doesn't come with case. The Sunrise MoonSound fits the medium size Philips NMS 1250 modem case. The OPL4 Shockwave is the largest.


Three OPL4 cartridges together


  • Yamaha YMF278B OPL4 sound synthesizer
  • 100% OPL1/OPL2/OPL3 compatible (note: the MSX-AUDIO is also OPL1 compatible, so MSX-AUDIO software that doesn't use the MSX-AUDIO ADPCM part can be used on the OPL4)
  • OPL4 has an independent CPU with its own memory so even a slow 3,58 MHz MSX computer is able to replay high quality samples with minimum of CPU power
  • Wave table part: 24 PCM channels (stereo: adjustable in 16 steps for each channel; replay frequency up to 44.1kHz)
  • Replay of 8-bit, 12-bit or 16-bit data
  • support for 2MB of Sample-RAM for own samples
  • FM synthesizer
    • 18 2-operator FM channels
    • 15 2-operator FM channels + 5 FM drums
    • 6 4-operator FM channels + 6 2-operator FM channels
    • 6 4-operator FM channels + 3 2-operator FM channels + 5 FM drums
  • 2MB wave table ROM (Yamaha YRW-801) with (approx.) 330 samples, mostly 22kHz 12-bit
  • Compatibility with the General MIDI standard (128 melody sounds and 47 percussion sounds)

Here's an example which shows how the Yamaha OPL4 can perform.

Software that uses the OPL4


  • Coral 2 (Infinite)
  • Golden Power Disc 12
  • News2004 (Infinite)
  • Sphere (Infinite)
  • TeddyWareZ XMas 2002 (TeddyWareZ)
  • Underwater Demo (Team Bomba)
  • Wings (Infinite)
  • Woei Demo (Team Bomba)


  • ASO Remake (Junsoft)
  • Battle Bomber (BitBoyz)
  • Bombaman (Team Bomba)
  • Blox (Team Bomba)
  • Bubble Rain (Imanok)
  • Cat 'n' Mouse (Imanok)
  • Dream Puzzle (Mapax)
  • Invaders (Junsoft)
  • Findit - Metal Gear Solid Edition (Delta Soft)
  • Findit Replayer (Delta Soft)
  • Green Gravity Guy (Bitvision)
  • Highway Fighter (Kai Magazine)
  • Life on Earth (Kai Magazine)
  • Life on Mars (Kai Magazine)
  • Myths and Dragons (Kai Magazine)
  • Oss 2000 Puzzel (Delta Soft)
  • Pumpkin Adventure III (Umax)
  • Rune Monster (Kai Magazine)
  • Sector 88 (Kai Magazine)
  • Sonyc (Analogy)
  • The Lost World (Umax)
  • Thunderbirds Are Go (Delta Soft)
  • Thunderbirds to the Rescue (Delta Soft)


  • IMS Player (Youngman Seo)
  • NMPMOD Player (NOP)
  • Moonblaster for Moonsound
  • MS² (TNI) (4MB mode)
  • VGMplay (Grauw) (4MB mode)
  • RoboPlay (RoboSoft)
  • RoboSID (Robosoft)