Gearbox Grind

How it's made

Source

mismatched steel teeth collide at 40–150 contacts/s, slowing under load. Each contact is a 0.4 ms attack and 3–9 ms filtered noise burst; timing jitter represents uneven damaged teeth.

Body

damped inharmonic gear and casing modes at 310, 731, 1390 and 2670 Hz, scaled by gear size, ring for 35–115 ms. Bearings add a quiet 100–700 Hz rough vibration, not a tonal motor note.

Friction

650–5200 Hz noise is chopped at the falling tooth rate; a moving broad band follows load. Three pressure surges at 0.08, 0.48 and 0.86 s suggest repeated unsuccessful engagement.

Envelope

12 ms onset, grinding through 1.12 s, release by 1.30 s, casing settles by 1.43 s. The final 70 ms is silent; no room reverb is baked in.

Variation

seeded contact timing, strength and mode detuning; size, tooth speed, wear and engagement loss distinguish heavy jam, fast fine teeth, interrupted mesh and worn coarse gears.

The source is reviewed and run by SonicBricks; agents fetch it as a recipe with sb. It is not published on this page.