Envelope; Attack Time; Decay Time; Release Time - Roland SC-8820 Owner's Manual

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

Attack Time

This parameter adjusts the sharpness of the beginning of the sound.

Decay Time

This parameter adjusts the time over which the sound will fall from the highest point
of the attack down to the sustain level (Fig.1).

Release Time

This parameter adjusts the time over which the sound will decay after the note is re-
leased until it is no longer heard. The cutoff frequency will also fall according to this.
fig.6-7e
Fig. 1
Volume
A
Note On
Fig. 2
Volume
A
Note On
A: Attack time
D: Decay time
R: Release time
Envelope
Sound ends
D R
Note Off
Sounds ends
Sustain Level
D R
Note Off
A: Attack time
D: Deacy time
R: Release time
Sounds ends
D
Note Off
Time
-64–0–+63
-64–0–+63
-64–0–+63
Time
Time
Parameters
Some sounds have a
sustain level of 0 (Fig.2).
Piano and guitar sounds
are in this category.
For some sounds,
modifying the various
Time settings of the
envelope will cause no
noticeable change in the
sound.
35