Edirol SD-80 - Manual (Page 35)

35
Using the internal sound generator
Using the internal sound generator
Envelope
fig.p8-3j
The sound of a musical instrument changes over time from the
moment the note begins until it ends. Such change can be expressed
by the graph shown below. The shape of this change is distinctive of
that particular instrument, and is an important factor that allows us
to recognize the type of instrument. This shape is called the
“
envelope .”
fig.p9-1j
The envelope of a musical instrument sound will
change depending on how the instrument is played. For
example, when a trumpet is blown strongly, the sound
will have a sharp and rapid attack, but when blown
gently, the attack will be softer.
To adjust the sharpness of the attack, you can edit the
Attack Time of the envelope. By adjusting the envelope
parameters in this way, you can express a wide variety
of the characteristics of an instrument.
The shape of the envelope that you specify in this way
will also affect the movement of the
cutoff frequency .
If the cutoff frequency is lowered, it will rise as the envelope rises and fall as the envelope falls.
Release Time (TVF&TVA Release) [cc#72] -64–0–+63
This adjusts the time from when you release the key (note-off message) until the sound decays to silence.
The cutoff frequency will also fall accordingly.
Attack Time (TVF&TVA Attack) [cc#73] -64–0–+63
This adjusts the sharpness with which the note begins.
Decay Time (TVF&TVA Decay) [cc#75] -64–0–+63
This adjusts the time from when the attack has been completed until the sustain level is reached (figure 1).
* For some sounds, the sustain level is 0 (figure 2). For example, this is the case for piano or guitar-type sounds.
* For some sounds, adjusting the various envelope times may not make any audible difference.
fig.p9-2j
Level
Cutoff frequency
Frequency
Low pass filter characteristics
Envelope
A D R
Cutoff frequency
Filter
Level
Note On Note Off
Time
Sound ends
A: Attack time
D: Decay time
R: Release time
A: Attack time
D: Deacy time
R: Release time
figure 1
A D R
A D
Time
Time
Sounds ends
Sounds ends
Note Off
Note Off
Note On
Note On
Volume
Volume
figure 2
Sustain Level