Multiply one oscillator (the carrier) by another (the modulator) and two new tones appear — sidebands at the sum and difference of the two frequencies. The only difference between the two effects is the carrier: ring modulation uses a bipolar modulator so the carrier cancels and you hear only the metallic sidebands; AM keeps the carrier and adds the sidebands around it (its depth sets how much). Sweep the modulator up past the carrier and the lower sideband folds through 0 Hz — that's the clangorous ring-mod sound.
play with your keyboard (a s d f …) or click the keys