furnace/papers/doc/7-systems/opll.md
2023-05-21 00:21:51 +02:00

63 lines
No EOL
2.5 KiB
Markdown
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# Yamaha YM2413/OPLL
the YM2413, otherwise known as OPLL, is a cost-reduced FM synthesis sound chip, based on the Yamaha YM3812 (OPL2). thought OPL was downgraded enough? :p
OPLL also spawned a few derivative chips, the best known of these is:
- the famous Konami VRC7. used in the Japan-only video game Lagrange Point, it was **another** cost reduction on top of the OPLL! this time just 6 channels...
- Yamaha YM2423, same chip as YM2413, just a different patch set
- Yamaha YMF281, ditto
# technical specifications
the YM2413 is equipped with the following features:
- 9 channels of 2 operator FM synthesis
- A drum/percussion mode, replacing the last 3 voices with 5 rhythm channels
- 1 user-definable patch (this patch can be changed throughout the course of the song)
- 15 pre-defined patches which can all be used at the same time
- Support for ADSR on both the modulator and the carrier
- Sine and half-sine based FM synthesis
- 9 octave note control
- 4096 different frequencies for channels
- 16 unique volume levels (NOTE: Volume 0 is NOT silent.)
- Modulator and carrier key scaling
- Built-in hardware vibrato support
# effects
- `11xx`: set feedback of channel.
- `12xx`: set operator 1 level.
- `13xx`: set operator 2 level.
- `16xy`: set multiplier of operator.
- `x` is the operator (1 or 2).
- `y` is the multiplier.
- `18xx`: toggle drums mode.
- 0 disables it and 1 enables it.
- only in drums chip.
- `19xx`: set attack of all operators.
- `1Axx`: set attack of operator 1.
- `1Bxx`: set attack of operator 2.
- `50xy`: set AM of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` determines whether AM is on.
- `51xy` set SL of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` is the value.
- `52xy` set RR of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` is the value.
- `53xy`: set VIB of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` determines whether VIB is on.
- `54xy` set KSL of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` is the value.
- `55xy` set EGT of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` determines whether EGT is on.
- `56xx`: set DR of all operators.
- `57xx`: set DR of operator 1.
- `58xx`: set DR of operator 2.
- `5Bxy`: set KSR of operator.
- `x` is the operator (1-2). a value of 0 means "all operators".
- `y` determines whether KSR is on.