Ym2413+instrumentsbin -

It sounds like you're asking for an analysis or a technical paper on the YM2413 (an FM synthesis chip) and its associated instruments binary file (often named instruments.bin or similar). The YM2413 is also known as the OPLL (FM Operator Type-L), used in MSX computers, Sega Master System add-ons, and some arcade boards.

Why do we need it?

While the chip has 15 hardcoded sounds, many games and demos rely on the User Instrument Slot (Instrument #0) to create unique sounds. A file like instruments.bin stores the parameters for these custom sounds.

3. The instruments.bin File

instruments.bin is a raw binary file containing one or more 8-byte YM2413 patches. Common uses: ym2413+instrumentsbin

Because limitations breed creativity. The YM2413’s "one user patch plus 15 presets" forces you to be clever. You use the instruments.bin not as a library, but as a secret weapon. By swapping that file between the verses and chorus of a song (impossible on real hardware, but easy in an emulator), you can achieve a unique "patch morphing" effect that modern synths cannot replicate.

Because it was so affordable, the YM2413 became the heartbeat of several iconic systems: It sounds like you're asking for an analysis

MAME (Multiple Arcade Machine Emulator)

MAME is strict about checksums. If you replace the default instrument bank, you must run:

Instruments.bin

The term "instruments.bin" likely refers to a binary file that contains instrument definitions or sound data for use with audio hardware, possibly including the YM2413. In the context of audio chips like the YM2413, such a file would contain the patches or instrument settings that define how the chip generates sound. These could include definitions for waveforms, envelope settings, and other parameters that determine the sound produced by the chip. Yamaha (1986)

8-byte structure (per instrument):

| Byte | Parameter | Description | |------|-------------------------|-------------| | 0 | Feedback / Algorithm | Bits 0-2 = algorithm (1 or 0), bits 3-5 = feedback | | 1 | Operator 1 (Carrier) | Multiplier, total level (MSB), KSR, etc. | | 2 | Operator 2 (Modulator) | Same as above | | 3 | Operator 3 (Carrier) | Same as above | | 4 | Operator 4 (Modulator) | Same as above | | 5 | Attack / Decay 1 | AR (4 bits) + DR (4 bits) for operator 1 | | 6 | Attack / Decay 2 | AR + DR for operator 2 | | 7 | Sustain / Release (all) | SR (4 bits) + RR (4 bits) for all operators |

References

1. Yamaha (1986). YM2413 Application Manual.
2. Mitsutaka Okazaki (2010). OPLL/OPL2/OPL3 programmer's reference.
3. Furnace Tracker documentation – YM2413 instrument format.
4. MAME source code – ym2413.cpp.