Doepfer A-114 Dual Ringmodulator - Manual (Page 4)

A-114 Dual Ring Modulator System A - 100 doepfer
4
Ring modulation of audio signals
A ring modulator is very good at doing weird things to
audio signals (for instance, voices, strings, sax).
The example at Fig. 2 shows an audio signal (input via
module A-119 "Ext. In") ring modulated with a sine
wave. The spectrum at the output contains the sum
and difference of the frequency of the sine wave with
every single one of the components of the audio
signal’s sound spectrum.
Fig. 2: Ring modulation of an external audio signal.
In this patch, the A-119 performs two functions.
On the one hand, it’s bringing the level of the external
signal up to the A-100’s operating level (round about 5
V
SS
).
On the other hand, it’s also sending the envelope
follower output (the envelope generated by the exter-
nal audio signal) to a VCA. This is necessary because
the ring modulator doesn’t completely shut off when
there’s 0V input. The VCO is still just audible, at
approximately -50 to -60dB, even when there’s no
external audio signal. The VCA gates it completely.
P Experiment with this set-up, for instance by
replacing the sine wave with other wa-
veforms (eg. sawtooth, square wave, etc.)
The waveform you use can itself also be
modulated (for instance by PWM, AM, FM,
or audio signal).
V CO
X IN
A-114
Y IN
X • Y OU T
RI NG MO D.
A-119
VCA
ext .
A udio In
Audio Out
Env. Out