Bronze Gong

How it's made

Source

a large bronze gong hit once by a soft felt mallet. The strike is a 10–25 ms low-passed thud (300–1800 Hz) that mostly excites the lowest modes; a harder mallet is shorter and brighter.

Body

a thin, slightly dished bronze disc has dozens of dense, inharmonic modes (≈ 1 : 1.47 : 1.98 : 2.63 : 3.21 : 3.92 …, up to ~20 × the fundamental). Low modes ring 4–8 s, upper ones fade within 1–2 s. Each mode is a close pair a fraction of a hertz apart, so the tail beats and shimmers.

Bloom

the disc is nonlinear, so energy migrates from the low modes into the upper ones over the first second. It is modelled as a second bank of 28 high modes (3–20 × f0) driven by a slowly swelling, band-limited noise instead of the mallet, so the brightness arrives after the strike and peaks at `bloom` seconds.

Wash

the swelling upper bank is blended with two decorrelated, resonant noise bands whose centres drift slowly, giving a wide, dense inharmonic wash with gentle shimmer (slow tremolo at 3–6 Hz).

Envelope

instant strike, swell peaking at 0.5–2 s, then a long fall over `decay` seconds, closed by a smooth fade so the oneshot ends cleanly.

Variation

`rng` mistunes every mode by ±0.6 % and draws the upper-mode frequencies.

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