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Table Of Contents
Resonance
The resonance control emphasizes or suppresses signals around the cutoff frequency.
The figure below shows an ES1 sawtooth wave with a high resonance setting and the
cutoff frequency set to 660 Hz, which is about 60%.
This resonant filter setting results in much brighter and harsher signals close to the cutoff
frequency. Frequencies below the cutoff point are unaffected.
Once again, the overall result of using filter resonance is a change in the basic waveforms
shape and, therefore, its timbre.
Very high filter resonance settings can be used to such an extreme degree that the filter
begins to self-oscillate, resulting in the filter generating a sine wave.
Drive
Drive adds an amount of gain to the waveform as it enters the filter—an input gain
control—thus overdriving the filter and distorting the waveform. This waveform distortion
changes the timbre of the sound, making it much harsher. See Reshaping Waveforms for
more information about waveform distortions.
The figure shows an unfiltered sawtooth wave, with Drive set to about 80%. Notice that
the wave cycles touch the floor and ceiling of the filters dynamic range.
360 Appendix Synthesizer Basics