Doepfer A-129-1/2 Vocoder Basic Modules - Manual

doepfer System A - 100 Modular Vocoder A-129 /1/2
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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 carrier signal, which is pat-
ched via the instrument input into the synthesis sec-
tion.
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 sec-
tion are external, using patch-leads, you can use this
interface to patch in your choice of modules (eg.
attenuator, slew limiter, CV-to-MIDI / MIDI-to-CV inter-
faces,, 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 arbitra-
rily, 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) can re-
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).