Waldorf Blofeld Keyboard - Manual (Page 97)

Sound Synthesis Basics
97 Blofeld User´s Manual
To give you an idea of the extent of damping, consider
this example of a low pass filter: A reduction of 24dB
reduces the original level one octave above the cutoff
point by approx. 94%. The damping factor two octaves
above the cutoff point reduces the original level by more
than 99%, which in most cases means this portion of the
signal is no longer audible.
The Blofeld’s filter also features a resonance parameter.
Resonance in the context of a low, band or high pass filter
means that a narrow frequency band around the cutoff
point is emphasized. The following picture shows the
effect of the resonance parameter on the filter’s frequency
curve:
If the resonance is raised to a great extent, then the filter
will begin self-oscillation, i.e. the filter generates an
audible sine wave even when it does not receive an
incoming signal.
Frequency
Level
Cutoff
Frequency
Level
Cutoff
Resonance