You can create custom patches using:
Example of a simple sine wave patch (hex): ym2413+instrumentsbin
00 00 00 00 00 0F 0F F0
In the 1980s, game composers often had to write assembly code to program the User Instrument slot. Today, modern tracker software allows musicians to edit these parameters via a GUI. When a user designs a new synth bass or a sound effect, the tracker exports this into an instruments.bin file. This file is then bundled with the song data, ensuring that the MSX hardware (or an emulator like openMSX) plays the music exactly as the composer intended. You can create custom patches using:
MAME is strict about checksums. If you replace the default instrument bank, you must run: Example of a simple sine wave patch (hex):
mame msx2_cart -cart game.rom -ioport:opll_file ym2413_instruments.bin
You may also need to recompile MAME to bypass the SHA1 integrity checks for software lists.