User Guide

124
Module: Silver
Filter basics
Filters alter sounds by cutting (also called
dampening and attenuating) certain ranges of their
frequency spectrum. A filter enables infinite
variations on the same sound material – anything
from subtle changes to total metamorphosis.
Musicians distinguish between two filter types, both
of which are found in Neuron. One is called a
shelving filter. This type of filter kicks in at a specific
frequency and achieves maximum effect at the edge
of the audible range. High-pass and low-pass filters
are shelving filters. The other basic filter type is
called a peaking filter. The shape of its curve inspired
the name. Peaking filters address the frequencies
surrounding a specific frequency - as band-pass
filters and band-stop filters are wont to do.
Neuron currently offers four shelving filters and one
peaking filter, which are described in detail on
page 125. Further filter types are in the works!
Filter parameters
Every filter, regardless of type, is defined by three
parameters. The cutoff frequency is the frequency
at which the filter starts working. Frequencies are
dampened or cut above or below the cutoff frequency
depending on the filter type (high-, low- or band-
pass page 125). In Neuron, you can vary the cutoff
frequency in real-time by moving the stick controller
in silver or modulating it via a filter envelope, LFO
oscillation or velocity. The cutoff frequency sweeps
through a specific frequency range, which is why this
process is called a filter sweep.
• Resonance: One property of filters is that they
boost the frequencies in the immediate vicinity
of the cutoff frequency. The higher the
resonance, the more the frequencies
surrounding the cutoff frequency (or the center
frequency in the case of band-pass filters) are
boosted in relation to other frequencies. This
makes the filter’s characteristic effect more
prominent than at low resonance values.
If the resonance of a filter is very high, the
filter begins oscillating on its own (that is
without an input signal) at the cutoff
frequency.
Geared toward synthesizer newbies, the following
section offers introductory explanations on the
basics of filtering. Seasoned keyboardists and
sound designers may prefer to continue reading on
page 127.
Neuron.book Seite 124 Montag, 23. Dezember 2002 2:28 14