Yamaha YC Series Owner's Manual page 35

Filter
Filter is a function that changes the tone of a sound by passing or only a specific frequency range and cutting signals in
other frequency ranges. The YC61 controls the following two characteristics with a single knob.
Cutoff
Determines the cutoff frequency of the filter (which frequency
band signal or higher is cut), adjusting the brightness of the
sound. Higher values result in a brighter sound.
Volume
Cutoff Frequency
These frequencies are
"passed" by the filter.
How these two characteristics change with a single knob operation is referred to as Filter control type. The YC61 has
seven types. The type can be set using the [EXIT] button + [EG FILTER] knob operation, or from the "Filter Control"
(page 43).
Graphs below show how the two parameters change when the knob is turned from the center (= 64) to the left and right in
each type.
Flat Reso
A type which uses the knob
to change only the Cutoff.
Flat Reso
0 64 127
Reso Minus A/B/C
Types which reduce the Resonance by turning the knob to the right. Characteristics of
the Filter function are strongly emphasized, letting you create synthesizer-like sounds.
Reso Minus A Reso Minus B
0 64 127 0
Reso Boost A/B
Types which increase the Resonance regardless of whether the knob is turned left or
right. Characteristics of the Filter function are strongly emphasized, and the sound gets
brighter when turning the knob to the right compared to the Reso Minus types.
Reso Boost A Reso Boost B
0 64 127 0
Frequency
Cutoff range
(pitch)
Reso Plus
A type which increases the Resonance
by turning the knob to the right.
Reso Plus
0 64
Reso Minus C
64 127 0 64
64 127
Resonance
Determines the amount of the resonance which raises the
volume around the cutoff frequency. Higher values result in a
more pronounced effect.
Volume
127
127
EG/Filter Control Type List
Resonance
Frequency
(pitch)
Cutoff
Resonance
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YC61 Owner's Manual