Roland MV-8800 Appendices page 57

VCF (Virtual VCF)
This reproduces, virtually, the VCF (Voltage Controlled
Filter). The sounds from the VCO or input from external
sources are processed with a filter that moves the cutoff
frequency as needed, and creates brightness (or hardness)
in the tone and changes in tone brightness over time. There
is a mixer to set the input level from each of the sound
generators at the input section of the VCF.
Mixer
• OSC1 (Oscillator 1)
• OSC2 (Oscillator 2)
• Noise
• ExtIn
• Ring M
Value: 0–100
Sets the input level to the VCF from each of the sound
generators. Mute unneeded sounds by setting them to 0.
Type
Sets the type of filter used.
Value Explanation
LPF Low pass filter. Passes frequencies below the cut off
frequency.
BPF Band pass filter. Passes frequencies near the cut off
frequency.
HPF High pass filter. Passes frequencies above the cut off
frequency.
BEF Band eliminate filter. Passes frequencies other than
those near the cut off frequency.
Curve
Value: -12 dB, -24 dB
Sets the filter's slope characteristics at the cutoff
frequency (-24 dB at one octave: steep; -12 dB at one
octave: shallow).
• Some analog synthesizers featured -12 dB/octave, -24
dB/octave, or other slopes.
Cutoff (Cutoff Frequency)
Value: 0–100
Sets the filter's cutoff frequency. Set this closer to zero,
the cutoff frequency becomes lower; set closer to 100,
the cutoff frequency becomes higher.
This setting varies with the addition of changes from the
envelope, LFO, and other changes.
Reso (Resonance)
Value: 0–100
Sets the filter's resonance level. Raising the setting
increases resonance near the cutoff frequency, giving
the sound a special characteristic.
• If the resonance value is raised to much, extreme
oscillation can arise. Take care not to allow this sound
to damage your ears or your playback equipment.
Envelope
• Depth (Envelope Depth)
Value: -100–100
Sets the depth of the Filter Envelope (the function of
changing the filter's frequency characteristics over
time).
• A (Attack Time)
Value: 0–100
The elapsed time starting at the point Trigger In is
switched "On" to the point at which the cutoff
frequency reaches the peak value.
• D (Decay Time)
Value: 0–100
The elapsed time from the point at which the cutoff
frequency reaches the peak value until reaching to the
sustain level (next item).
• S (Sustain Level)
Value: 0–100
The level of the cutoff frequency after the decay time
(previous item) is passed and until Trigger In is
switched "Off."
Effect Block
A-57
MV-8800 Appendices