User manual

9User Guide Action Filter 4
EN
Can a band pass through the lter or will it be rejected?
What happens if you combine a high- and lowpass filter? There are two possibilities: a serial or a
parallel routing - one after the other or both next to each other.
In series, high- and lowpass form a so-called bandpass. In the Action Filter 4, a highpass will first
remove lower frequencies. From here the signal is send into a lowpass, where higher frequencies
are processed.
Figure 3:
INPUT
FILTER A: Highpass
OUTPUT
FILTER B: Lowpass
Serial combination of high- and lowpass filter
What remains is a frequency band of a certain width which is specified by both CUTOFF controls.
By likewise moving both CUTOFFs to the left or right, this band is moved across the frequency
spectrum.
Figure 4:
CUTOFF
Highpass
CUTOFF
Lowpass
LEVEL
FREQ.
Bandpass filter: the green area is being passed through the filter whereas the red area is
rejected.
The Action Filter 4 allows independent control for the high- and lowpass filter and therefore a
free bandwidth by adjusting both CUTOFF controls to different values. In addition, the filters’
resonance controls can be set individually and therefore create different enhancements at the lower
and upper cutoff-frequencies. This particular feature of the Action Filter 4 allows creation of sounds
not possible using typical bandpass filters with a fixed width.