Roland Sound Canvas SC-8850 Owner's Manual page 66

Creating a Sound or Drum Set
Cutoff Freq (Cutoff Frequency)
Positive settings of Cutoff Freq will raise the cutoff frequency. Negative settings will
lower the cutoff frequency. As you set this value higher in the positive direction,
more overtones will be allowed to pass, and the sound will become harder (brighter).
The further this value is set in the negative direction, the fewer overtones will be al-
lowed to pass, and the sound will become softer (darker).
fig.6-4e
Low pass filter characteristics
Level
Cutoff frequency
Resonance
When the Resonance value is increased, the overtones in the area of the cutoff fre-
quency will be emphasized, creating a sound with a strong character.
fig.6-5e
Level
Cutoff frequency
Low
Envelope
The volume of an instrument changes with time, from the moment the note begins
to sound to when it disappears. This change can be indicated on a graph as shown
in the following diagram. This shape is unique to each instrument, and is an impor-
tant element in how we distinguish sounds we hear. This shape is called the enve-
lope.
The envelopes of musical instrument sounds can change depending on how the in-
strument is played. For example, if a trumpet is played sharply and strongly, the at-
tack will be quick and the sound will be sharp. But if a trumpet is played lightly and
softly, the attack will be softer. In order to adjust the attack of a sound, we can modify
the Attack Time of the envelope. By modifying the values of the envelope we can
simulate the characteristics of many different instruments.
The envelope shape that we create in this way will also affect the way in which the
cutoff frequency changes. If the cutoff frequency had been lowered, it will rise as the
envelope rises, and will fall as the envelope falls.
fig.6-6e
Cutoff frequency
Level
A
Note On
66
Frequency
Frequency
High
Resonance
A: Attack time
D: Decay time
R: Release time
Envelope
Sound ends
D R
Note Off
-64–0–+63
-64–0–+63
Time
For some sounds, positive
(+) settings of Cutoff Freq
will cause no noticeable
change in the sound.
For some sounds, negative
(-) settings of Resonance
will cause no noticeable
change in the sound.