Ring Modulators

Ring modulation first starting appearing in modern and experimental music in the early ’50s, though it has a parallel history in the radio industry, where it was used to enable stereo broadcast of FM signal from radio waves. While ring modulators have a practical function, musicians and instrument builders alike were intrigued by the radical musical potential of the technology. Pioneer synth builder Don Buchla incorporated a simple ring-mod circuit into his groundbreaking Buchla 100 Modular Synthesizer in 1963. At about the same time, revolutionary composer Karlheinz Stockhausen began scoring music that called for numerous ring modulators to be used to process pianos, trumpets, and flutes in a live performance setting.

Where You’ve Heard It
During the solo of Black Sabbath’s heavy metal super-hit “Paranoid,” guitarist Tony Iommi makes use of a ring modulator to add a fuzzy, stuttering element to his already fuzzy tone. But its most recognizable uses are often in soundtrack work, where they lend a sci-fi aura.

How to Use It
At its core, ring modulation is an amplitude modulation effect. Without getting too technical, your input signal is essentially joined with an oscillator signal known as a carrier wave. When the signals interact some are canceled and others are enhanced. The carrier wave is generated by the ring mod effect and most ring mods have a control to set the pitch of the carrier wave. If the carrier wave pitch is lowered below the level of human hearing (~20hZ) then the resulting ring mod will produce the stuttering effect described above in “Paranoid.”

LFO Off, Drive at 3 o'clock, Mix at noon, Frequency Modulation at 15 Hz

Higher pitched settings of the carrier wave produce audible resonant frequencies, like those inherent to tuned percussion instruments like bells, chimes, and pipes.

Blend at 10 o'clock, Modulation rate controlled by expression pedal.

Blend - The ring mod effect is similar to pitch shifters, delay and reverb effects in the sense that the effect is enhanced by having the dry signal present. For this reason it would be challenging to use a ring mod pedal without a blend control.

Waveform - Many ring mod pedals, such as the Electro-Harmonix Ring Thing and the Way Huge Ringworm, will allow you to determine the waveform shape of the carrier wave. This may be sine, triangle, sawtooth, square, ramp, or others. Changing the carrier waveform will allow you a greater ability to shape your tone. In the same way that a sine wave has a softer sound than a sawtooth wave, so will a sine carrier wave in a ring mod pedal produce a softer overall tone than a sawtooth carrier wave.

Pitch - The ring mod effect can be difficult to grasp and master, but it can produce tones and timbres that are impossible to achieve using any other means. Most of the difficulty in controlling the effect stems from controlling the pitch of the carrier wave. A little experience and trial-and-error experimentation with the ring mod can go a long way, and place a wealth of timbres is at your fingertips.

Some ring mod circuits like the Pigtronix Mothership with its “Intelligent Ring Mod” function, can read your guitar’s pitch and use that to tune the carrier wave. Most ring mod pedals purposefully do not have this ability as the ring mod effect produces its most interesting results when the carrier wave and your incoming signal are harmonically dissimilar. On the majority of ring mods, a pitch knob or expression pedal control bends the carrier wave on a continuous plain from low to high frequencies. In other words, the possibilities are nearly endless.

Pedals We Tested
Way Huge Ringworm - Way Huge is one of those pedal builders that seems to just get everything right. Their well-built pedals marry simple layouts with excellent tones, and their Ringworm ring modulator is no exception. The five relatively straightforward controls enable you to get you up-and-running in no time and yet the pedal has enough depth to keep you coming back for more. The Ringworm has all of the standard controls including Blend and Frequency (also controllable via expression pedal input), but it also has selectable waveform modes, among other controls. The waveform modes add an extra level of tone shaping capability to an otherwise pristine-sounding ring mod circuit. These modes include square-wave modulation (for 1950s flying saucer sound), random (for 1950s flying-saucer-on-drugs sound), envelope follower (for laser blasts), and standard triangle & sine waves modes. The Ringworm is capable of going totally far-out but it also handles standard bell-like ring mod timbres and swimming psychedelic tones with ease.

Electro-Harmonix Ring Thing - EHX has a long history in many worlds of guitar effects, including ring modulation. In 1978 they release their first ring mod pedal dubbed the Frequency Analyzer. Like the Analyzer, the Ring Thing is a ring mod, but it’s also a pitch shifter, a tremolo, a rotary-speaker emulator, and more. The Ring Thing packs tons of features including numerous expression pedal inputs, preset storage, waveform selection, multi-function knob controls, and a filter.

Four operating modes set the Ring Thing even further apart and include ring mod, upper sideband modulation (processes only the high frequencies), lower sideband modulation (processes on the low frequencies), and pitch shift settings. Each of these modes enables you to modulate frequencies via the unit’s range of multi-function knobs. The Ring Thing can do 8-bit style video game tones, vintage sci-fi tones, rich harmonic ring mod timbres, trippy filter tremolos, and sub-octave pitch shifting, among other sounds.

Dwarfcraft Hax - When Dwarfcraft sits down to make a pedal that does X, they’ll inevitably wind up with something that does X8*#jfi%a))@7wwwWWW1. That goes for their entry into the ring mod world, the Hax. The Hax is a blistering ring mod pedal with a huge pitch range made possible by a footswitch that selects between HI frequency range and LOW frequency range. The unit also includes a tasty fuzz circuit with a voltage starve control called CRASH for creating phenomenal gated fuzz tones that clash gloriously with the ring mod tones. Control of the carrier wave frequency is made possible via control knob or expression pedal. The minimal controls on the Hax make it very easy to get cool sounds without endless tweaking. The interaction of the ring mod circuit with the distortion circuit is phenomenal. You can use the ring mod subtly to create a unique and slightly off-kilter fuzz tone that sounds quite unlike any other pedal. On the other hand, you can crank the ring mod and blast the fuzz circuit to create strange sounds and textures that are completely outside known solar systems.

Moog Moogerfooger MF-102 Ring Modulator - One ring to rule them all. One Moog to find them. It’s hard to imagine modern music without Robert Moog’s legendary sonic inventions. For one thing, it would be a lot less weird.

Moog’s MF-102 Ring Modulator is essentially a modular synth section in a stompbox with some built-in connectivity for guitarists. The layout is very guitarist-friendly, and cool effects like bell-like tones, tremolo, spacey swirls, alien space vehicles, and beyond, are attainable through just a few intuitive knob twists. An internal LFO can be used to add movement to the carrier wave, which really opens up more swirling and bending possibilities. A drive control is also included so you can overdrive the unit introduce a bit of warm, analog distortion.

Moog’s wares are typically top-of-the-line quality, bordering on luxurious, and this particular Moogerfooger is no exception. The 100 percent analog circuitry delivers superb sound quality and warm, well-defined tones that are studio worthy. The MF-102, like its modular forebearers, is built with interconnectivity in mind. Nearly all parameters are controllable via control voltage (CV), which enables you to wire the unit to a wide range of other gear, including other Moogerfoogers. When it comes to sonic clarity and definition, Moogerfoogers are king.

Z.Vex Ringtone - Z Vex’s Ringtone is one of the most unique entries in the ring mod stompbox world. It’s built around an eight-step sequencer that makes it possible to adjust the carrier pitch independently at each step. The sequencer scans across eight LEDs that represent each step and a tiny potentiometer under each LED to adjust the pitch of that step. You can also set the speed of the sequencer either via tap-tempo or potentiometer. A three-position switch allows you to shorten the sequence to 4 steps or completely randomize the sequencer.

The sequencer produces rhythmic changes to the ring mod setting, producing a range of sounds from telephone auto-dialer to jumbled robot babble. By turning down the ring mod mix and throwing a reverb in the chain you can use the Ringtone to create some subtle, shifting textures, perfect for that extra flavor to set your tone apart. The wet/dry mix, meanwhile can be set via a control inside the unit, which may be the only drawback of the small enclosure, but it’s a more than fair trade given how many unique sounds there are within.