Yamaha MU80 Owner's Manual page 62

MULTI MODE
Vibrato Depth
Graphically shows Vibrato Depth setting for each Part.
Vibrato Delay
Graphically shows Vibrato Delay setting for each Part.
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This determines the speed of the Vibrato effect. Higher values result
in a faster Vibrato sound.
Selected Part and MIDI channel
This determines the depth of the Vibrato effect. Higher values result
in a stronger, more pronounced Vibrato sound.
Selected Part and MIDI channel
This determines the delay in the onset of the Vibrato effect. Delay is
effective especially on stringed instrument Voices. For example, vio-
lin players often use delayed vibrato, especially while playing long
notes. The Delay parameter is useful in recreating this effect, pro-
ducing a more natural, lifelike sound. Higher values result in a
longer Delay time.