Waldorf Pulse 2 User Manual
Page 65
Appendix
65
Pulse 2 User Manual
Control Change (Controllers)
MIDI messages enable you to manipulate the response
of a sound generator to a significant degree.
This message essentially consists of two components:
• The Controller number, which defines the element
to be influenced. It can be between 0 and 119.
• The Controller value, which sets the extent of the
modification.
Controllers can be used for effects such as slowly swel-
ling vibrato and influencing filter frequency.
Decay
"Decay" describes the descent rate of an envelope once
the Attack phase has reached its zenith and the envelo-
pe drops to the level defined for the Sustain value.
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,
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 programed 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
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
categories: 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 frequencies below the cutoff. The band pass filter
allows only those frequencies around the cutoff fre-
quency 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.