Parametric Filters - E-Mu Proteus 1000 Operation Manual

Parametric Filters

A more complex type of filter is called a parametric filter or Swept EQ. A
parametric filter allows control over three basic parameters of the filter. The
three parameters are: Bandwidth, Frequency and Gain. The Bandwidth allows
you to select the width of the range of frequencies to be boosted or cut, the
Frequency defines the center frequency of the bandwidth, and the Gain
parameter either boosts or cuts the frequencies within the selected band by
a specified amount. Frequencies not included in the selected band are left
unaltered. This is different from a band-pass filter which attenuates
(reduces) frequencies outside the selected band.
+18 dB
0 dB
-18 dB
The parametric filter is quite flexible. Any range of frequencies can be either
amplified or attenuated. Several parametric sections are often cascaded in
order to create complex filter response curves.
If four parametric filter sections were cascaded, it would be possible to
create the following complex filter response.
20
15
10
5
0
-5
Many natural instruments have complex resonances which are based on
their soundboard or tube size. The resonance shown above would be impos-
sible to create using a normal synthesizer filter.
Freq.
Boost
Bandwidth
Cut
Frequency
4 Parametric Equalizers
500 10,000
Linear Frequency - Hertz
Proteus 1000 Operation Manual 77
Programming Basics
Dynamic Filters
Parametric
Filter
15,000 20,000