by Francis Preve
Lately, I’ve been getting a slew of questions about ring modulation. With effects like Apple Logic’s Ringshifter, Propellerhead Reason’s Scream, and Ableton Live’s Frequency Shifter, there are a lot of DAWs that are ready-made to ring modulate audio and soft synths of all flavors.
First things first. The concept behind ring modulation (ring mod for short) is that it applies audio-rate modulation to the amplitude of the incoming signal in a bipolar manner (standard amplitude modulation operates in unipolar fashion, a subtle difference, but one worth noting). The end result is that ring mod generates two additional frequencies that are the sum and difference of the input signal and the ring mod frequency. For example, if your original tone is a sine wave at 100Hz and the ring mod frequency is 300Hz, the result will be four frequencies: 100, 200, 300, and 400Hz. More complex input signals generate even wilder results.
With the math out of the way, let’s take a look at some practical applications for this mysterious effect.
Pick Up the Phone
As mentioned, the more complex the input signal, the more complex and distorted the effect. As a result, sine waves and ring mod go together like milk and cookies. Take your favorite sine-wavecapable synth and create a simple, unfiltered, single-oscillator sine wave patch with a simple gated envelope. Then apply a 1kHz ring modulator to the synth. If you play a riff in the octave beginning with middle C, the results will be quite similar to the DTMF tones you hear on your phone, which can be a really cool effect in the right context.
Last year I used a ring mod effect on the congas in my singles “Flotsam” and “Jetsam.” Since congas, bongos, and similar percussion instruments have a lot of pure tone after the initial attack transients, these are also excellent candidates for the effect. If your ring mod effect includes an LFO that can sync to tempo, even better. Try a sine wave LFO synced to quarter-notes and increase the amount until the drums start to wobble and bounce. Eighth-notes and half-notes are also groovy. Use your ears and experiment.
Ring mod on vocals can create “helium” effects that are a lot more spacey and techno than a simple pitch shifter. Robot voices? Talking toys? No problem. In this audio example, I took a small snippet of Meredith Call’s lead vocal from last year’s Winter Kills single, “My Friend,” and drenched it in ring mod at a frequency of 700Hz.