Doepfer A-129-1-2 User Manual
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System A - 100
Modular Vocoder
A-129 /1/2
1. Introduction
The A-129 /x series of modules forms a modular
vocoder. ‘Vocoder’ is an abbreviation of ‘voice coder’.
The basic components are an analysis section
(A-129 /1) and a synthesis section (A-129 /2).
Like a ring modulator, the vocoder needs two input
signals: a speech element which serves as the raw
material for the tonal shaping, and is patched into the
analysis section; and a
ched via the instrument input into the synthesis section.
The speech signal is chopped up and analysed in the
A-129/1 module, and then combined with the carrier
signal in the A-129/2 synthesis section. As a result of
this procedure, the carrier signal assumes the tonal
character of the speech signal, but with its own pitch
maintained.
Since the A-129 is a modular vocoder, and the
connections between the analysis and synthesis section are external, using patch-leads, you can use this
carrier signal
, which is pat-
interface to
attenuator, slew limiter, CV-to-MIDI / MIDI-to-CV interfaces,, inverter, etc.).
The
Five-way VC slew limiter / offset generator /
attenuators (A-129 /3) and Slew controllers (A-
129/4) are particularly designed for this purpose.
There’s also the possibility of connecting the frequency
bands of the analysis and synthesis sections arbitrarily, so that, for instance, a low frequency band in the
speech signal can control a high frequency band in the
carrier signal.
The
Voiced / unvoiced detector (A-129 /5)
cognise voiced and unvoiced sections in the speech
signal, and switch the carrier signal accordingly.
The A-129 /2 synthesis section can also be used as a
stand-alone voltage-controlled filter bank (see
chapter 6, User examples).
patch in
your choice of
modules
can re-
(eg.
1
A-129 /1/2
Modular Vocoder
2. A-129 /1, /2 - Overview
System A - 100
doepfer
Speech
Input
High Pass
Out
A-129 /1
VOCODER ANALYSIS SECTION
Low Pass
Band 1
Band 2
Band 3
Band 4
VOC-A
Band 5
Band 6
Band 7
Band 8
Band 9
Control Voltage Outputs
Band 10
Band 11
Band 12
Band 13
High Pass
A-129 /2
VOCODER SYNTHESIS SECTION
Instrument
Input
Vocoder
Output
Low Pass
Band 1
Band 2
Band 3
Band 4
Band 5
Band 6
Band 7
Band 8
Band 9
Control Voltage Inputs
VOC-S
Band 10
Band 11
Band 12
Band 13
High Pass
2
doepfer
System A - 100
Modular Vocoder
A-129 /1/2
In / Outputs:
A-129 /1
Speech In : Input for the speech signal
!
CV Outputs
"
High Pass
§
A-129 /2
Instrument In : Input for the instrument signal
$
CV Inputs : 15 CV inputs
%
Vocoder Out
&
The following Table 1 shows the cut-off frequency of
the low pass filter, the middle frequency of the band
pass filters (Band 1 to Band 13) and the cut-off
frequency of the high pass filter.
: 15 CV outputs with control LEDs
: Signal output from the high pass
filter
: Audio output from the vocoder
Filter Frequency Filter Frequency
Low Pass
Band 1
Band 2
Band 3
Band 4
Band 5
Band 6
Band 7
100 Hz
120 Hz
160 Hz
230 Hz
330 Hz
500 Hz
750 Hz
1.1 kHz
Band 8
Band 9
Band 10
Band 11
Band 12
Band 13
High Pass
1.3 kHz
1.6 kHz
2.3 kHz
3.3 kHz
5 kHz
7.5 kHz
10 kHz
Tab. 1: Filter frequencies in the analysis and synthe-
sis sections
3
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