Sword Clash

How it's made

Source

two steel blades meeting edge to edge. Contact lasts about 1 ms, so each blade is excited by a broadband, high-passed click; the second blade is struck a few ms later and slightly off axis, which doubles the transient into a sharp "tk-tch". A short scrape follows as the edges slide past each other.

Body

a thin blade is a free-free bar. Its flexural modes are inharmonic, at about 1 : 2.76 : 5.40 : 8.93 : 13.3 times the lowest mode (300-1100 Hz). Steel is lightly damped, so the lowest modes ring for up to `ring` seconds while the upper ones die within 0.1-0.3 s. The two blades differ in length and stiffness (`mismatch`), so their mode sets interleave and beat against each other instead of reinforcing.

Scrape

band-passed noise whose centre rises from 2.5 kHz to 6 kHz over about 0.3 s, shaped by a rough random amplitude (stick-slip friction) and a fall in force. It also feeds the blade modes, so the sliding noise picks out the metallic resonances instead of sounding like a bare hiss.

Envelope

instant attack, exponential decay per mode (T60 up to `ring`, 1 s by default); the output is closed by a fade after the longest mode, so the one-shot ends at about 1.2 s.

Variation

`rng` mistunes every mode by up to 0.6 %, varies the click and the friction texture. Macros: `pitch` is blade length and mass, `brightness` the strength of the upper modes, `scrape` the amount of sliding contact, `mismatch` the tuning gap between the blades.

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