Ym2413+instrumentsbin

This is by design. As explained above, modern MAME requires this external file to load the chip's instrument data for legal and architectural reasons. You need to source this file from a proper ROM set, sometimes as part of the ym2413.zip BIOS file.

mame msx2_cart -cart game.rom -ioport:opll_file ym2413_instruments.bin

The Konami VRC7, which is a derivative of the YM2413, has its own famous set of patches that are highly sought-after by chiptune artists, including unique sounds like "Buzzy Bell," "Wurly," and "Sweep". ym2413+instrumentsbin

That’s the practical answer:

The ym2413_instruments.bin file is a small binary file (usually 160 bytes) that acts as a of the YM2413’s internal Instrument ROM . This is by design

In summary, "ym2413+instrumentsbin" relates to the YM2413 audio chip and its associated instrument configurations or presets, reflecting a piece of audio history in the world of early computing and video gaming.

(Note: The YM2413 actually expects this data to be packed into specific register bits. The binary file usually stores the raw values which are then bit-shifted before being sent to the chip.) mame msx2_cart -cart game

Released in the mid-1980s, the YM2413 was a stroke of engineering genius. Yamaha sought to bring FM (Frequency Modulation) synthesis to the mass market. While its bigger brother, the YM2151, powered arcade cabinets, and the YM2612 became famous in the Sega Genesis, the YM2413 was designed for home computers like the MSX2+ and the Korean Master System.

The binary file contains the specific modulator/carrier multipliers, feedback rates, and envelope generator variables that define these 15 factory voices: YM2413 missing rom - Arcade Controls Forum

Sets how quickly the sound starts and fades.