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 Lagrange Point by Konami.

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

Note: The chip is limited to only one user defined patch, so it's not possible to use different user defined patches in different channels at the same time! Please see documents about YM2413 or documents about FM in general if you need more information.

Note release command can be used on these channels, it will enable the sustain flag.

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.

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
RATE key scale | Increases the ADSR rate for higher pitches | on / off
Key Scale Level | The attenuation level for RATE, according to table 2 | 0 - 3
Wave rectification | Half wave rectification of the sine wave | on / off
Multiplication factor | Multiplies the pitch with 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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