See waves.
[toc]
Clipping
Soft clipping
f(y) = y - 1/κ · y^κ for an odd integer κ.
Wave folding
f(y) = τ - (y-t) if y > 1 else y
Feed an old copy of the signal back.
f(t) = signal[t] + α · f(t - dt)
For if the delay is in a specific range, then it will alter the frequency spectrum. It will emphasize and de-emphasize harmonics.
Ranges: chorus - flange - delay
Combine multiple tuned delay lines.