Give a clean digital file the character of a turntable playback: pitch that drifts instead of holding steady, occasional surface clicks, and a top end that falls away instead of extending to 20 kHz.
Wobble
The pitch wobble comes from reading a short delay line at a position that moves back and forth, not from resampling. Two low-frequency oscillators drive the read position at once: a slow one for wow and a faster one for flutter, combined so wow dominates the motion and flutter adds a quicker shimmer on top.
The Speed control sets both rates together, matching the pitch instability a faster-spinning disc produces compared to a slower one.
Crackle
Surface noise here is a stream of short, randomly timed clicks rather than continuous hiss, each one a brief decaying impulse at a random level. Raising Crackle increases how often a click lands, not how loud each one is.
Tone
The Tone control is a low-pass filter corner frequency. Turntable playback rarely reaches the extended highs of a digital source, so pulling this down toward 5 to 8 kHz removes the digital edge that would otherwise sit on top of the wobble and crackle.
Mix
Mix blends the processed signal against the original, from 0% (untouched) to 100% (fully wobbled, crackled, and filtered). Lower settings let the wobble and crackle sit under a mostly clean signal instead of taking it over completely.
Example: a clean vocal take, aged
Speed 33⅓, wobble 40%, crackle 25%, tone 7000 Hz.
The pitch drifts audibly under sustained notes, occasional clicks sit under the quiet passages, and the reduced top end pulls the recording back from a digital source toward something closer to a record spinning in another room.