Audio Damage Filterstation User Manual
Page 7
notch is controlled by the resonance control; a higher resonance value makes the notch narrower, cutting
fewer of the frequencies. This means that, unlike the other filter types, increasing the resonance setting of a
notch filter usually creates a less-dramatic filtering effect.
Filters are also often characterized by their number of poles
1
. The more poles a filter has, the more it
attenuates frequencies. For instance, a 4-pole low-pass filter will attenuate frequencies above its corner
frequency more than a 2-pole low-pass filter with the same frequency setting. While Moog synthesizers are
justifiably famous for their 4-pole low-pass filters, filters with fewer poles also have their uses. Most early
Korg and Oberheim analog synthesizers, for instance, employed 2-pole filters.
Filterstation contains all of the aforementioned filter types, most with variants with different numbers of poles.
There are also a few that have the same basic type and number of poles, but individual sonic characteristics,
i.e. different variations on a theme.
1
Why the term ―poles‖? It has to do with the mathematics used to design filters, and it‘s something of a long story. See for
example
if you‘re really curious.