81 lines
3.8 KiB
Markdown
81 lines
3.8 KiB
Markdown
# Yamaha OPL
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a series of FM sound chips which were very popular in DOS land. it was so popular that even Yamaha made a logo for it!
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essentially a downgraded version of Yamaha's other FM chips, with only 2 operators per channel.
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however, it also had a [drums mode](opll.md), and later chips in the series added more waveforms (than just the typical sine) and even a 4-operator mode.
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the original OPL (Yamaha YM3526) was present as an expansion for the Commodore 64 and MSX computers (erm, a variant of it). it only had 9 two-operator channels and drums mode.
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its successor, the OPL2 (Yamaha YM3812), added 3 more waveforms and was one of the more popular chips because it was present on the AdLib card for PC.
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later Creative would borrow the chip to make the Sound Blaster, and totally destroyed AdLib's dominance.
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the OPL3 (Yamaha YMF262) added 9 more channels, 4 more waveforms, rudimentary 4-operator mode (pairing up to 12 channels to make up to six 4-operator channels), quadraphonic output (sadly Furnace only supports stereo) and some other things.
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afterwards everyone moved to Windows and software mixed PCM streaming...
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# effects
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- 10xx: set AM depth. the following values are accepted:
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- 0: 1dB (shallow)
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- 1: 4.8dB (deep)
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- this effect applies to all channels.
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- **`11xx`**: set feedback of channel.
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- **`12xx`**: set operator 1 level.
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- **`13xx`**: set operator 2 level.
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- **`14xx`**: set operator 3 level.
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- only in 4-op mode (OPL3).
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- **`15xx`**: set operator 4 level.
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- only in 4-op mode (OPL3).
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- **`16xy`**: set multiplier of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode).
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- `y` is the multiplier.
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- 17xx: set vibrato depth. the following values are accepted:
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- 0: normal
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- 1: double
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- this effect applies to all channels.
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- **`18xx`**: toggle drums mode.
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- 0 disables it and 1 enables it.
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- only in drums chip.
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- **`19xx`**: set attack of all operators.
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- **`1Axx`**: set attack of operator 1.
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- **`1Bxx`**: set attack of operator 2.
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- **`1Cxx`**: set attack of operator 3.
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- only in 4-op mode (OPL3).
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- **`1Dxx`**: set attack of operator 4.
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- only in 4-op mode (OPL3).
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- **`2Axy`**: set waveform of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` is the value.
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- only in OPL2 or higher.
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- **`30xx`**: enable envelope hard reset.
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- this works by inserting a quick release and tiny delay before a new note.
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- **`50xy`**: set AM of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` determines whether AM is on.
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- **`51xy`**: set SL of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` is the value.
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- **`52xy`**: set RR of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` is the value.
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- **`53xy`**: set VIB of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` determines whether VIB is on.
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- **`54xy`**: set KSL of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` is the value.
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- **`55xy`**: set SUS of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` determines whether SUS is on.
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- **`56xx`**: set DR of all operators.
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- **`57xx`**: set DR of operator 1.
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- **`58xx`**: set DR of operator 2.
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- **`59xx`**: set DR of operator 3.
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- only in 4-op mode (OPL3).
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- **`5Axx`**: set DR of operator 4.
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- only in 4-op mode (OPL3).
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- **`5Bxy`**: set KSR of operator.
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- `x` is the operator (1-4; last 2 operators only in 4-op mode). a value of 0 means "all operators".
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- `y` determines whether KSR is on.
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