Modification de Le modulateur en anneaux

Here is an excerpt from an old Electronic Music Review from Jan 1967 written by Harold Bode using diode ring and transformer "multiplier-type" ring modulator. Some nice examples of how this type ring modulator can be configured. Most interesting is Ex 8 where two ring modulator are configured to make a "tunable filter". Harold did use UTC brand A-20 transformers that had a wide frequency range in his ring modulators. I like the idea of this heterodyne effect of higher frequencies. Never tried this patch though?

Quote Harold Bode
"Among all signal processors the multiplier-type ring modulator takes a unique
position, since it is capable of converting existing sounds into new (and
pleasing) sounds with entirely different overtone spectra that do not resemble
the original acoustical phenomena. A few examples will illustrate some
typical applications of this sound processing tool and the results obtained .

Ex. 1: A 1000 Hz sine wave is applied to the program input and a 900 Hz
sine wave to the carrier input. The output contains two frequencies, 100 Hz
and 1900 Hz. If the magnitudes of the inputs are both 1.0 volt RMS,the
magnitude of the total output of the described standard model will also be
1.0 volt RMS.
Ex. 2: The program input receives a 1000 Hz square wave and the carrier
input receives a 900 Hz sine wave. A square wave contains an infinite series
of discrete frequencies, all of which are odd multiples of the fundamental.
The output therefore consists of two infinite series, one of which is the sum
of the 1000 Hz square wave components and the 900 Hz sine wave, and the
other of which is the difference.
Ex. 3: Program input is filtered white noise with a bandwidth of 0 to 100 Hz
and carrier input is a 900 Hz sine wave. This noise spectrum contains equal
energy per unit bandwidth from 0 to 100 Hz. The output of the modulator
is a spectrum centered at 900 Hz, but containing an equal distribution of
frequencies from 800 Hz to 1000 Hz. Note that the bandwidth of the output
is twice the bandwidth of the program input. When sweeping the carrier
frequency of this setup over the center portion of the audio range, the sound
of a howling wind may be simulated . A similar but more complex effect will
be obtained when the program input is white noise with a bandwidth of, for
instance, 400 to 500 Hz. In this case a carrier of 900 Hz would generate two
white noise bands, one from 400 to 500 Hz and one from 1300 to 1400 Hz.
Naturally, "tuned" white noise may cover a lesser bandwidth and thereby
result in more selective effects.
Ex. 4: The program material is supplied by a voltage-controlled oscillator
which operates in the sine wave mode and is controlled by a keyboard.
The carrier signal is supplied by a second voltage-controlled oscillator in
the sine wave mode, controlled by the same keyboard and tuned relative to
the first oscillator by a frequency ratio of 3:4, or any rational number. In
case these integers do not have a common denominator, the resulting funda-
mental frequency and its overtones at the output will be of a very attractive
quality due to slow timbre changes, which may result from an intentional
detuning of the two input frequencies relative to the theoretical multiples
of the fundamental frequency.
Ex. 5: Very interesting effects with the speaking or singing voice may also
be obtained by feeding the fundamental voice frequency (obtained through
a lowpass filter) into one input and the entire voice spectrum into the other.
In this case the application of an efficient automatic gain control to the
fundamental frequency (with the aid of a voltage-controlled amplifier) would
be required, in order to retain the original dynamic properties of the input
sounds.
Ex. 6: When feeding the program material (preferably music and very effec-
tively, organ music) into the carrier input and a low frequency sine wave
in the vibrato range (for instance, 6 Hz) into the program input, a special
modulation effect will be created, and will be remarkably enhanced if the
same program material is reproduced directly (without modulation) through
a second amplifier and speaker system . The result will be a kind of spatial
amplitude-phase modulation .
Ex. 7: Percussive sounds in the category of Trinidad drums are obtained when
the sounds of bass drums, tom toms, temple blocks, wood blocks, claves, and
maracas are fed into the program input and an audio frequency in the lower
to middle audio range into the carrier input.
Ex. 8: When the program material is heterodyned into a higher frequency
range, say 10,000 to 20,000 Hz (with the aid of an oscillator of appropriate
frequency feeding into the carrier input), and the new spectrum is passed
through a narrow band filter in said frequency range, and the filtered fre -
quencies heterodyned back into the audio range by applying the same
oscillator frequency to the carrier input of a second ring modulator, the effect
of a tunable filter is obtained when the oscillator frequency is changed .

From these examples, which merely scratch the surface of the possible appli-
cations of the multiplier-type ring modulator, it will become evident that
this instrument is a very powerful tool for the electronic music composer, and
that the variety of results obtainable is as limitless as the imagination of
the user."
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	Here is an excerpt from an old Electronic Music Review from Jan 1967 written by Harold Bode using diode ring and transformer "multiplier-type" ring modulator. Some nice examples of how this type ring modulator can be configured. Most interesting is Ex 8 where two ring modulator are configured to make a "tunable filter". Harold did use UTC brand A-20 transformers that had a wide frequency range in his ring modulators. I like the idea of this heterodyne effect of higher frequencies. Never tried this patch though?		Here is an excerpt from an old Electronic Music Review from Jan 1967 written by Harold Bode using diode ring and transformer "multiplier-type" ring modulator. Some nice examples of how this type ring modulator can be configured. Most interesting is Ex 8 where two ring modulator are configured to make a "tunable filter". Harold did use UTC brand A-20 transformers that had a wide frequency range in his ring modulators. I like the idea of this heterodyne effect of higher frequencies. Never tried this patch though?