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Editing the C64 instrument doc.

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Edits for style consistency and clarity (I hope).
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Electric Keet 2023-11-02 22:47:51 -07:00
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doc/4-instrument/c64.md
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@ -5,7 +5,8 @@ the C64 instrument editor consists of two tabs: "C64" to control various paramet
## C64
- **Waveform**: allows selecting a waveform.
- more than one waveform can be selected at once. in that case logical AND mix of waves should occur, bit actually a weird bit mixing occurs (due to the hardware flaws; 6581 and 8580 models handle those "combined waves" differently).
- more than one waveform can be selected at once. in that case a logical AND mix of waves will occur...
- due to hardware flaws, the mixing is a bit weird and sounds different between the 6581 and the 8580.
- noise is an exception. it cannot be used with any of the other waveforms.
- **Attack**: determines the rising time for the sound. the bigger the value, the slower the attack. (0 to 15).
- **Decay**: determines the diminishing time for the sound. the higher the value, the longer the decay (0 to 15).
@ -24,7 +25,7 @@ the C64 instrument editor consists of two tabs: "C64" to control various paramet
- **high**: a high-pass filter. higher cutoff values result in a less "bassy" sound.
- **band**: a band-pass filter. cutoff determines which part of the sound is heard (from bass to treble).
- **ch3off**: mutes channel 3 when enabled. not sure why is this part of the chip's design, but it is.
- Different filter modes can be selected simultaneously, e.g. low+high. The resulting sound would be as if input was passed through lowpass filter and then highpass filter (or vice versa, you get the idea).
- multiple filter modes can be selected simultaneously. for example, selecting both "low" and "high" would combine the effects of both, resulting in a bandpass filter.
- **Absolute Cutoff Macro**: when enabled, the cutoff macro will go from 0 to 2047, and it will be absolute (in other words, control the cutoff directly rather than being relative).
- **Absolute Duty Macro**: when enabled, the duty macro will go from 0 to 4095.
@ -43,12 +44,17 @@ the C64 instrument editor consists of two tabs: "C64" to control various paramet
- **Resonance**: filter resonance sequence.
- **Special**: ring and oscillator sync selector, as well as:
- **gate bit**:
- set (1) = key on, if previous state was 0 it triggers envelope start/restart, if previous state was 1 does nothing
- reset (0) = key off, if previous state was 1 it triggers envelope release, if previous state was 0 does nothing
- set (1): key on. if previous state was 0 it triggers envelope start/restart; if previous state was 1, it does nothing.
- reset (0): key off. if previous state was 1 it triggers envelope release; if previous state was 0, it does nothing.
- **test bit**:
- set (1) = channel immediately muted (if the channel is a source of ring mod and/or hard sync those stop working until you reset the bit)
- reset (0) = unmute channel, restore ring mod/hard sync functionality described above
- **Attack**: sets envelope attack speed. If you modify attack speed when envelope is in attack phase it immediately changes.
- **Decay**: sets envelope decay speed. If you modify decay speed when envelope is in decay phase it immediately changes.
- **Sustain**: sets envelope sustain level. If you modify sustain level when envelope is in sustain phase it immediately changes, although you can only go down (e.g. 9->8 and 8->8 works, but if you go 8->9 channel immediately mutes itself).
- **Release**: sets envelope release speed. If you modify release speed when envelope is in release phase it immediately changes.
- set (1): immediately mute channel
- if the channel is a source of ring mod and/or hard sync, those stop working until the bit is reset.
- reset (0): unmute channel and restore ring mod/hard sync.
- **Attack**: sets envelope attack speed.
- if you modify attack speed when the envelope is in attack phase it immediately changes.
- **Decay**: sets envelope decay speed.
- if you modify decay speed when envelope is in decay phase it immediately changes.
- **Sustain**: sets envelope sustain level.
- if you modify sustain level when envelope is in sustain phase it immediately changes, although you can only go down. for example, 9-to-8 and 8-to-8 both work, but 8-to-9 immediately mutes the channel.
- **Release**: sets envelope release speed.
- if you modify release speed when envelope is in release phase it immediately changes.