Yamaha MOTIF ES Owner's Manual page 161

Filter
[VOICE] Voice selection
Drum Key selection [F3] FILTER
This unit modifies the tone of the sound output from Pitch by
cutting the output of a specific frequency portion of the sound.
Cutoff Frequency and Resonance
Here's how filters work. In the example below (a low pass
filter), a portion of the signal lower than a given frequency is
allowed to pass, and signals above that frequency are cut.
This frequency is referred to as the cutoff frequency. You can
produce a relatively bright or darker sound by setting the
cutoff. Resonance is a parameter that boosts the level of the
signal in the area of the cutoff frequency. By emphasizing the
overtones in this area, this can produce a distinctive "peaky"
tone, making the sound brighter and harder.
Cutoff frequency
Level
These frequencies are "passed" by the filter.
Level
Cutoff frequency
About the main Filter types
The Low Pass Filter is shown in the illustration above –
however, this synthesizer features other Filter types (four total)
as shown below.
Low Pass Filter (above)
This passes only those signals below the Cutoff frequency.
You can then use the Reso (Resonance) parameter to add
further character to the sound.
High Pass Filter
This passes only those signals above the Cutoff frequency.
You can then use the Reso (Resonance) parameter to add
further character to the sound.
Level
Resonance
Cutoff frequency
[EDIT] Element selection/
Frequency (pitch)
Resonance
Frequency (pitch)
These frequencies are
"passed" by the filter.
Internal Structure (System Overview)
Band Pass Filter
This passes only those a band of signals around the Cutoff
frequency. The width of this band can be varied.
Range passed
Level
Center frequency
Cutoff range
Band Elimination Filter
This attenuates a band of signals around the Cutoff
frequency, but passes everything else.
Level
Center frequency
Range passed
FEG (Filter Envelope Generator)
Using the FEG, you can control the transition in tone from the
moment the sound starts to the moment the sound stops. You
can create the FEG by setting parameters as illustrated
below. When you press a note on the keyboard, the cutoff
frequency will change according to these envelope settings.
This is useful for creating automatic wah or filter sweep
effects, for example. Furthermore, different FEG parameters
can be set for each Element Key.
Attack
Cutoff
Level
Frequency
Decay1
Hold
Level
Level
0
Hold Attack
Decay1
Time Time
Time
Pressing the key (Key on)
Frequency
Cutoff range
Frequency
Sustain Level
Release
(Decay2 Level)
Level
Time
Release
Decay2
Time
Time
Releasing the key (Key off)
Owner's Manual
161