Waldorf Nave - Manual (Page 67)

Appendix
67 Nave User Manual
Envelope
An envelope is used to modulate a sound-shaping com-
ponent within a given time frame so that the sound is
changed in some manner. For instance, an envelope that
modulates 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, usu-
ally a fixed trigger. Normally, the trigger is a MIDI Note.
The classic envelope consists of four individually variab-
le phases: Attack, Decay, Sustain and Release. This se-
quence 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 programed Sustain level. This level remains
constant until the trigger is terminated. The envelope
then initiates the Release phase until it reaches the mini-
mum value.
Filter
A filter is a component that allows some of a signal’s
frequencies to pass through it and dampens other fre-
quencies. The most important aspect of a filter is the filter
cutoff frequency. Filters generally come in four catego-
ries: low pass, high pass, band pass, and band stop. A
low pass filter dampens all frequencies above the cutoff
frequency. A high pass filter in turn dampens the fre-
quencies below the cutoff. The band pass filter allows
only those frequencies around the cutoff frequency to
pass, all others are dampened. A band stop filter does
just the opposite, i.e. it dampens only the frequencies
around the cutoff frequency. The most common type is
the low pass filter.
Filter Cutoff Frequency
The filter cutoff frequency is a significant factor for filters.
A low pass filter dampens the portion of the signal that
lies above this frequency. Frequencies below this value
are allowed to pass through without being processed.
High Pass Filter
A high pass filter dampens all frequencies below its
cutoff frequency. Frequencies above the cutoff point are
not affected.
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 compo-
nent.