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Chapter 3 ES2 40
Use ring modulation in ES2
Ring modulation is a powerful tool for the creation of inharmonic, metallic, bell-like sounds. The
spectra resulting from its use are inharmonic at almost every frequency ratio. The ring modulator
is a device that dates back to the early days of the synthesizer.
A ring modulator has two inputs. At the output you hear both the sum and dierence
frequencies of the input signals. If you ring modulate a sine oscillation of 200 Hz with a sine
oscillation of 500 Hz, the output signal of the ring modulator consists of a 700 Hz (sum) and a
300 Hz (dierence) signal. Negative frequencies result in a change to the phase polarity of output
signals.
Tip: Use sawtooth and rectangular (pulse width modulated) input signals from oscillators 1 and
2, respectively, to create a much more complex output signal. The use of these harmonically rich
waveforms results in a number of extra sidebands becoming audible.
Create a ring-modulated sound
1 Set the oscillator 2 Wave knob to the Ring setting.
2 Experiment with dierent Frequency (main and ne tune) values for one, or both, oscillators.
The oscillator 2 ring modulator is fed with the output signal of oscillator 1 and a square wave,
generated by oscillator 2 itself. The pulse width of this square wave can be modulated (see Use
pulse width modulation in ES2 on page 38).