Roland SP-404MK Reference Manual page 192

Appendix MFX List
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Vocoder
Changes the voice to a vocoder voice.
This is enabled with INPUT FX.
Parameter Value
NOTE -17‒ -1, 1‒18
FORMANT -100‒100
TONE -100‒100
SCALE C maj‒B maj, C min‒B
min
CHORD Root, P5, Oct, UpDn,
UpDnP5, 3rd, 5thUp,
5thDn, 7thUp, 7thDn
BALANCE 100-0‒0-100
Explanation
Sets which note in the chromatic scale should sound, counting from the
root of the SCALE value. The scale and chord structure that is used
depends on the SCALE and CHORD settings.
The NOTE value can be controlled via note messages from a MIDI
keyboard connected to the MIDI IN connector, a computer connected via
USB, a DAW app running on an iOS device and so on.
At that time, you can send pitch bend messages to continuously change
the pitch.
For note messages (Note Number = 0‒127) and pitch bend messages,
set the MIDI channel on your external device to "11."
Adjusts the formant of the voice. Lower settings give a more masculine
vocal character, and higher settings give a more feminine vocal character.
Adjusts the brightness of the effect sound.
Sets the scale to use and its root.
Sets the chord structure.
Adjusts the volume balance between dry (the original sound) and effect
sound.