Appendix
212
Iridium Manual
lope’s current status. For instance, the Release phase may
be initiated during the Attack phase.
Resonance
Resonance is an important filter parameter. It emphasizes
a narrow bandwidth around the filter cutoff frequency by
amplifying these frequencies. This is one of the most popu-
lar methods of manipulating sounds. If you substantially
increase the resonance, to a level where the filter begins
self-oscillation then it will generate a relatively clean sine
waveform.
Spectrum
A basic component of sounds are periodic oscillations. The
perceived pitch corresponds to the fundamental frequency
of this oscillation. The frequency spectrum of periodic
oscillations is a line spectrum, the lowest frequency cor-
responds to the fundamental frequency (fundamental) and
other frequencies-integer multiples of the fundamental
frequency (harmonics). A spectrum display like that which
is in the Iridium is a graphical overview of all the frequen-
cies of a wavetable with their amplitudes over time.
Sustain
An envelope parameter. The term ‘Sustain’ describes the
level of an envelope that remains constant after it has run
through the Attack and Decay phases. Sustain lasts until
the trigger is terminated.
System Exclusive Data
System exclusive data allow access to the heart of a MIDI
device, enabling access to data and functions that no other
MIDI messages are able to address. ‘Exclusive’ in this
context means that this data pertains to only one device
type or model. Every device has unique system exclusive
data. The most common applications for SysEx data inclu-
de transfer of entire memories and complete control of a
device via a computer.
Trigger
A trigger is a signal that activates events. Trigger signals
are very diverse. For instance, a MIDI note or an audio
signal can be used as a trigger. The events a trigger can
initiate are also very diverse. A common application for a
trigger is use to start an envelope.
