SYNTHESIS · 02

AM and ring modulation.

Modulate the amplitude of a wave and watch new frequencies appear. Set depth to maximum to turn AM into ring modulation.

Volume35 %

Tremolo

SHAPE THE MODULATION

Carrier, modulator and depth

The modulator is slow: you will hear a periodic change in volume.

Carrier c440 HzThe frequency of the original sound Modulator m5 HzLogarithmic scale: 0.1 to 1000 Hz Depth d0,35No mod.100% AMRM

c − m435 Hzc440 Hzc + m445 Hz

time →

SignalEnvelope

frequency →

Relative amplitudes · fixed frequency scale: 0–2200 Hz

WHAT IS HAPPENING

With a modulator below about 20 Hz, we hear tremolo: the volume rises and falls rhythmically.

With an audio-rate modulator, two sidebands appear at c−m and c+m, alongside the carrier.

When d = 1, the carrier disappears. Only the sum and difference remain: this is ring modulation.