Konami VRC7

About

The VRC7 chip contains a customized OPLL unit (YM2413) that has 6 channels for frequency modulation synthesis. This chip was only used in the game Lagrange Point by Konami.

This chip has 15 predefined patches and can hold one user defined patch, the predefined patches are customized for VRC7 and are not the default ones for YM2413.

Note cut command will clear the key on flag, note release command will clear the key on flag but keep the sustained flag.

Note: The chip is limited to only one user defined patch, so it's not possible to simultaneously use different user defined patches in different channels! See documents about YM2413 if you need more information. The available headroom range is limited by this chip and clipping will occur when the total level is too loud, this occurs already when two channels are running at maximum volume, so keep the volume levels down.

Instruments

Instruments contains a patch setting and the parameters for the custom patch (patch #0). The predefined patches (patch #1 - #15) are defined in hardware and cannot be changed.

Use copy/paste to create and read MML strings from the clipboard of the patch settings.

The custom patch settings are enabled when patch 0 is selected and are used to customize the modulator and carrier oscillator, but it will also display the settings for the internal patches.

Note: when using sustained patches, use the note cut command to move on to the release phase. The note release command will also release the note, but does so at a fixed rate.

Parameter | Description | Range
Attack, Decay, Sustain, Release | ADSR envelope for the volume level. | 0 - 15
Amplitude modulation | Applies a fixed tremolo effect at 3.7 Hz | on / off
Vibrato | Applies a fixed vibrato effect at 6.4 Hz | on / off
Sustained | Switch between sustained and percussive tone | on / off
Key scaling | Increases the ADSR rate for higher pitches | on / off
Key scaling level | The attenuation level for key scaling, according to table 2 | 0 - 3
Wave rectification | Half-wave rectification of the sine wave | on / off
Multiplication factor | Multiplies the pitch by a factor, according to table 3 | 0 - 15
Feedback | Modulator feedback level | 0 - 7
Modulator Level | Modulator mixing level | 0 - 31

Table 1, Instrument parameters

Value | Rate
0 | 0 dB/oct
1 | 1.5 dB/oct
2 | 3 dB/oct
3 | 6 dB/oct

Table 2, Key Scale Level Table

Value | Factor
0 | ½
1 | 1
2 | 2
3 | 3
4 | 4
5 | 5
6 | 6
7 | 7
8 | 8
9 | 9
10 | 10
11 | 10
12 | 12
13 | 12
14 | 15
15 | 15

Table 3, Multiplication factor table

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