[naltroc]

that delightful "abyss" is really just noise. as in white/pink/blue noise.

Signals tend to sound "better" (richer harmonic content) when they have fuzz added. Convolution reverb is a great example of how mixing a noise sample into any source signal increases its apparent depth or richness.

Some saturators do the same thing.

Others distort the signal by boosting selected harmonics (making the waveform more square-like or more sawtooth-like for example, which is not the same as noise and has a different sound).

Clipping the signal by requesting amplitudes beyond the available range is another way to add "cruch" (noise) to a signal.

The actual implementation will vary per device but overall we like our sounds cut with a bit of noise.