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Included VST Instruments
Mystic
The synthesis method used by Mystic is based on three parallel comb filters with feedback.
A comb filter is a filter with a number of notches in its frequency response, with the notch
frequencies harmonically related to the frequency of the fundamental (lowest) notch.
A typical example of comb filtering occurs if you are using a flanger effect or a delay effect
with very short delay time. Raising the feedback (the amount of signal sent back into the
delay or flanger) causes a resonating tone – this tone is basically what the Mystic produces.
This synthesis method is capable of generating a wide range of sounds, from gentle plucked-
string tones to weird, non-harmonic timbres.
The basic principle is the following:
• You start with an impulse sound, typically with a very short decay.
The spectrum of the impulse sound largely affects the tonal quality of the final sound.
• The impulse sound is fed into the three comb filters, in parallel. Each of these has a
feedback loop.
This means the output of each comb filter is fed back into the filter. This results in a
resonating feedback tone.
• When the signal is fed back into the comb filter, it goes via a separate, variable low-
pass filter.
This filter corresponds to the damping of high frequencies in a physical instrument –
if this is set to a low cutoff frequency it causes high harmonics to decay faster than the
lower harmonics (as when plucking a string on a guitar, for example).
• The level of the feedback signal is governed by a feedback control.
This determines the decay of the feedback tone. Setting this to a negative value
simulates the traveling wave in a tube with one open end and one closed end. The
result is a more hollow, square wave-like sound, pitched one octave lower.
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