A ring modulator combines a signal from an instrument with a carrier signal generated by the ring modulator itself. The unit then outputs the sum and the difference of the two frequencies. For example, if you instrument is producing a 100hz signal and the ring modulator is generating a 600hz signal, you would hear a 700hz signal as well as a 500hz signal. You would not hear your original signal or the carrier signal. Because this process is mathematical rather than harmonic, the resulting sound is often very dissonant and has a bell-like metallic tone (hence the term “ring modulation”). For this reason, guitarists typically use ring modulators for textural embellishments for “art rock” noise.
Since ring modulators can create such atonal chaos, most come equipped with controls that can be used to create more musical tones. Frequency and blend are the most common controls provided on ring modulators. The first allows the player to tune the generated signal that will be mixed with the input, while the second enables the original input to be heard alongside the effect-enhanced output. By adjusting these two controls, you can temper the overtones, adding unusual textures to the recognizable input signal.
One of the earliest production ring modulators was the Dan Armstrong Green Ringer. This simplistic device was equipped with only a bypass switch, and its abrasive tone had limited appeal at the time. Later models like DOD’s Gonkulator Modulator added controls in addition to mix and frequency that altered the modulation character for a larger range of effects. Moog Music’s MF-102 gives you a choice of waveforms for the carrier signal, while the Frostwave Blue Ringer v2 has adjustable modulation and dual inputs that allow it to produce ring modulation from two input sources.
Ring modulators can also be found in some effects plug-ins and multi-effect processors like the Line 6 Modulation Modeler. Player with a lust for vintage minimalism should check WD’s Green Ringer reissue.