Spring Bounce

How it's made

Source

a body (or ball) compresses a coiled spring or trampoline bed and is thrown back. The contact is a 3–8 ms low-passed noise thump plus a short 70–130 Hz bed "thud" as the surface bottoms out.

Body

the stretched spring/membrane rings at a pitch set by its tension. Tension rises as the surface rebounds (pitch climbs ≈ 1.6–2.2× within 90–140 ms) and relaxes afterwards (falls to ≈ 0.7× over the rest of the sound). A sine fundamental carries the note, a triangle octave adds elastic body, and two inharmonic coil partials (≈ 2.76× and 5.4×) follow the same glide with a fast decay for the metallic "sproing".

Envelope

contact within 5 ms, the boing swells over ≈ 40 ms, then decays exponentially (≈ 0.3 s); the wobble depth decays faster than the level, so the pitch settles as the sound fades. Total ≈ 0.6 s.

Modulation

the elastic wobble is a 9–20 Hz sine vibrato on the frequency (up to ±9 %) whose depth falls exponentially; a slow random drift keeps each bounce from sounding mechanical.

Variation

`rng` shifts base pitch ±3 %, wobble phase and rate ±4 %. Macros: height (glide range and level), tension (base pitch), wobble (vibrato depth), metal (coil partials), thump (surface contact weight).

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