The ring modulator is best described as being a sound processing module. It has two sound inputs and a sound output. There really isn’t anything to adjust on a basic ring modulator it produces an output that is the sum of the two input signals mixed in with the difference of the two signals. However some of the more exotic versions have controls that can be tweaked.
With harmonically simple waveforms such as sine waves the output is fairly simple but once you put in something harmonically more complicated like a ramp wave the ring modulated output gets really complicated with all the overtones that are produced.
This makes the ring modulator an excellent starting source for producing sounds with a metal origin like bells and gongs. Incidentally a ring modulator was used to produce the dalek voice sound; apparently the BBC radio phonic workshop used a ring modulator and put a voice signal into one of the modulation inputs and a sine wave at about 30 Hertz into the other, giving the voice a harsh quality with metallic overtones.
Moog Music produce the excellent Moog Music MF102 Moogerfooger Ring Modulator Pedal and based on it the cheaper cut down MOOG MINIFOOGER Ring modulator you have tone, frequency and a mix control to enable you to produce the standard effects of harmonic discordance.
Another recently produced device is the Dunlop Way Huge WHE606 Ring Worm Modulator and although cheap it possesses blend and frequency controls,along with an LFO with five different waveforms of which you can also alter the rate and width.
But if your after versatility the ELECTRO HARMONIX RING THING takes some beating. Although intended as a guitar effects pedal you can of course put anything you like through it. You can get all the usual effects of bell type harmonic dissonances but you also get a pitch shifter built in which multiplies the amount of things you can get out of this along with its filtering and its also programmable so you store your favorite moments of brilliance. It does seem to be able to produce a lot of very musically useful effects as well as sheer madness which is probably down to the “single side modulation” which produces less inter-modulation, you can however still make huge cacophonies of sound.
Even more versatile than that though is the Pigtronix Mothership Synthesiser and Ring Modulator not only is it very advanced ring modulator but its also a guitar synthesiser with excellent tracking a a superb sound. The ring modulation produced by this device is “intellegent” in the fact the this one can track the input pitch so your sound output will keep the same intervals and harmonics regardless of what you play. this certainly makes for a hugely musical creation, especially when you mix it with the onboard synthesiser. Although this is the most expensive device featured here, its also the most versatile and also pretty amazing when you hear what it can do.