NEOGEO sounds system:
Co-processor: Zilog Z80 running at 4 MHz. This is also used as an audio controller
SoundSound chip: Yamaha YM2610
4 FM channels, 4 operators per channel
3 SSG channels
1 Noise channel
7 ADPCM channels
Work RAM (sound): 2KB
Sound ROM 128KB on-board (only less than 32KB used)
up to 512KB sound ROM on cartridges