Ring Modulation is a great synthesis tool we can use to design unique timbral dimensions with lush sonic elements. It is an extremely flexible and powerful synthesis technique. It's one of the most popular method for creating complex waveforms, which are the building blocks of sound.
In a few words ring modulation is the blend of two Oscillators which then creates a new one with the Sum and the Difference sidebands of those within the spectrum. The fundamental frequencies are filtered out of the new audio wave.
So let's say we have 2 sine waves in 500Hz and in 2000Hz. The result will be a new Oscillator that peaks in 1500Hz (difference) and 2500Hz (sum). The sine waves are the purest form of sound with just a single harmonic. If we now bring in the game audio waves with more harmonics like pulses, saws, complex wave tables we have a lush sound, often inharmonic.
With ring modulation we can create eerie synths with weird motion, ugly soundscapes with metallic timbres, distorted like pads, stressful sonic fields, experimental ambiences and thin drones among other types of synthesizer sounds.
Many software synths include this powerful tool in their arsenal. Omnisphere 2 by Spectrasonics has a very advanced RM section where we can combine very complex waveforms and adjust other settings for a great result. Arturia Pigments and CS-80 V4 contain Ring Modulation synthesis as well as Serum does.
I, as a synth sound designed, find the RM technique very intriguing and use it a lot for different applications from leads and polysynths to pads and textural ambiences. The richness of the new harmonics that come from this experimental tool are pretty much unexpected, especially when using more extreme settings. Many of our synth patches enclose Ring Modulation in their sound core - sometimes in a subtle way, sometimes in more apparent ways.