YM2610

Yamaha YM2610 OPNA2

Overview

The Yamaha YM2610, commonly known as OPNB, is a highly integrated sound chip developed by Yamaha.

It combines FM synthesis, programmable sound generation and ADPCM sample playback in a single device. The chip is most famously associated with the SNK Neo Geo arcade and home-console hardware.

The YM2610 is part of Yamaha's large family of FM sound chips and represents an important step towards combining synthesized and sampled audio in a single sound architecture.

Technical characteristics

• Manufacturer: Yamaha
• Model: YM2610
• Common name: OPNB
• FM channels: 4
• Operators: 4 per FM channel
• PSG channels: 3
• ADPCM channels: Multiple sample playback channels
• Synthesis: FM + PSG + ADPCM
• Typical system: SNK Neo Geo

FM synthesis

The YM2610 contains four channels of four-operator FM synthesis. This provides the same fundamental type of operator-based synthesis found in other Yamaha OPN-family chips.

FM synthesis can therefore be used for melodic instruments, basses, pads and other synthesized sounds.

Programmable sound generator

In addition to its FM section, the YM2610 contains a three-channel PSG compatible with the general Yamaha and AY sound-generator tradition.

This provides simple square-wave voices and noise generation that can be used alongside the FM channels.

ADPCM sample playback

One of the most important features of the YM2610 is its integrated ADPCM hardware.

Sampled audio can be used for drums, percussion, voices and other effects, while the FM section handles synthesized instruments.

This hybrid architecture was particularly effective in arcade games, where music and sound effects could require very different types of audio.

Neo Geo

The YM2610 is strongly associated with the SNK Neo Geo. Its combination of FM, PSG and ADPCM contributed significantly to the characteristic sound of Neo Geo games.

The system could combine synthesized music with substantial quantities of sampled sound effects and speech, something that was becoming increasingly important in arcade hardware during the early 1990s.

Tracker relevance

The YM2610 is highly relevant to tracker music because it combines several different music-generation approaches in one device.

A music driver can use FM synthesis for instruments, PSG channels for simpler voices and ADPCM for sampled material. This hybrid approach makes the YM2610 considerably more flexible than a conventional three-channel PSG.

Historical importance

The YM2610 represents an important stage in the evolution of Japanese arcade sound hardware. It combines the established Yamaha FM synthesis architecture with programmable sound generation and digital sample playback.

Its association with the Neo Geo makes it one of the most recognizable arcade sound chips of the early 1990s.

Related soundchips

• Yamaha YM2608 OPNA — Related FM/PSG/rhythm/ADPCM architecture.
• Yamaha YM2612 — Six-channel FM chip used in the Sega Mega Drive.
• Yamaha YMZ280B — Yamaha multi-channel PCM/ADPCM sound chip.
• Yamaha YM2151 — Four-operator FM synthesizer widely used in arcade hardware.

Further reading

• Wikipedia — Yamaha YM2610
• VGMRips — Yamaha YM2610
• Technical documentation — YM2610