Oki Semiconductor · 1987 · 1980s – 1990s · 4 voices
The MSM6295 was the workhorse sample-playback chip of the arcade industry — a four-channel ADPCM voice synthesiser that streamed drums, speech, and sound effects from ROM on more 1990s arcade boards than almost any other chip.
Where FM chips like the YM2151 synthesised sound from scratch, the MSM6295 played back recorded samples: it read four independent channels of ADPCM (adaptive differential pulse-code modulation) data from an external ROM of up to 256 kilobytes, decoding compressed audio into drums, digitised speech, and effects. This division of labour defined the sound of an entire arcade era — an FM chip carried the melody while the MSM6295 supplied the percussion and voice samples, and the combination gave games like Capcom's Final Fight and CPS-1 fighters their punchy, sample-driven character. Introduced around 1987, the chip was cheap, reliable, and easy to program, and it appeared on hundreds of boards from Capcom, Data East, and later the bullet-hell specialists at Cave. Its limited ROM budget forced sound designers into disciplined economy, reusing short samples across a whole game, and the slightly crunchy 4-bit ADPCM texture became an unmistakable signature of coin-op audio. Developers often paired two MSM6295s on a single board when they needed more channels or sample memory.