Doepfer A-128 Fixed Filter Bank User Manual
System a - 100, A-128, Introduction
doepfer
System A - 100
Fixed Filter Bank
A-128
1
1. Introduction
Module A-128 (Fixed Filter Bank) is a filter bank,
made up of 15 parallel band pass filters, all with
fixed middle frequencies and bandwidth:
50 Hz
350 Hz
2.2 kHz
75 Hz
500 Hz
3.6 kHz
110 Hz
750 Hz
5.2 kHz
150 Hz
1.1 kHz
7.5 kHz
220 Hz
1.6 kHz
11.0 kHz.
Each band pass filter has its own amplitude control
knob, with which that frequency band can be attenua-
ted. The bandwidth of each of the filters is approxi-
mately half an octave.
The signal at the output of the A-128 contains a mix of
all the filters, depending on the position of each one’s
amplitude control knob.
The filter bank’s main job is to emphasise individual
sections of the whole audio frequency range. It’s like
a passive 15-band EQ.
Audio
In
75 Hz
Audio
Out
A-128
Fixed
Filter
Bank
110 Hz
11 kHz
50 Hz
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