Waldorf STVC, Руководство пользователя

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Appendix
33 STVC Manual
Decay
‘Decay’ describes the descent rate of an envelope once the
Attack phase has reached its zenith and the envelope
drops to the level defined for the Sustain value.
Envelope
An envelope is used to modulate a sound-shaping compo-
nent within a given time frame so that the sound is chan-
ged in some manner. For instance, an envelope that modu-
lates the cutoff frequency of a filter opens and closes this
filter so that some of the signal's frequencies are filtered
out. An envelope is started via a trigger – usually a fixed
trigger. Normally the trigger is a MIDI Note. The classic
envelope consists of four individually variable phases:
Attack, Decay, Sustain, and Release. This sequence is called
an ADSR envelope. Attack, Decay, and Release are time or
slope values, and Sustain is a variable volume level. Once
an incoming trigger is received, the envelope runs through
the Attack and Decay phases until it reaches the pro-
grammed Sustain level. This level remains constant until
the trigger is terminated. The envelope then initiates the
Release phase until it reaches the minimum value.
Filter
A filter is a component that allows some of a signal's fre-
quencies to pass through it and dampens other frequenci-
es. The most important aspect of a filter is the filter cutoff
frequency. The most common type is the lowpass filter. A
lowpass filter dampens all frequencies above the cutoff
frequency.
Filter Cutoff Frequency
The filter cutoff frequency is a significant factor for filters.
A lowpass filter dampens the portion of the signal that lies
above this frequency. Frequencies below this value are
allowed to pass through without being processed.
LFO
LFO is an acronym for Low-Frequency Oscillator. The LFO
generates a periodic oscillation at a low frequency and
features variable waveshapes. Similar to an envelope, an
LFO can be used to modulate a sound-shaping component.
Low Pass Filter
Synthesizers are often equipped with a lowpass filter. A
lowpass filter dampens all frequencies above its cutoff