Acoustic Strum

How it's made

Source

six steel or nylon strings plucked in quick succession by a pick or thumb sweeping across them. Each string is a Karplus–Strong loop: a noise burst circulating in a damped delay line, so the attack is bright and the upper partials die first while the fundamental rings.

Strum

the six onsets are staggered over 20–140 ms (`strum`), low to high for a down-stroke and the reverse for an up-stroke. Later strings are slightly softer and each onset is jittered by ±2 ms.

Body

the soundboard and air cavity of the box colour all strings alike: an air resonance near 100 Hz with a top-plate overtone near 210 Hz and a broad presence bump near 2.4 kHz, added in parallel to the dry strings.

Envelope

low strings sustain longer (≈ 2 s) than the thin high ones (≈ 1.2 s); the whole chord is faded out by a closing envelope so the one-shot ends cleanly at about 2.5 s.

Variation

`rng` detunes every string by up to ±3 cents and varies pick strength and timing; the presets change chord voicing, strum speed, direction, brightness and sustain.

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