@audio/reverb-spring

Spring reverb — dispersive allpass-chain loop (Parker-Välimäki class simplified model)

npm install @audio/reverb-spring

import spring from '@audio/reverb-spring'

A feedback loop of 24 cascaded first-order dispersive allpass filters plus a short pre-delay: the cascade makes group delay frequency-dependent, producing the characteristic spring "boing"/chirp on transients. A simplified digital spring after Parker & Välimäki, "Spring reverberation: a physical perspective" (DAFx-10). Mono only.

spring(data, { decay: 0.6, tension: 0.5, damping: 0.4, mix: 0.35, fs: 44100 })
spring(data, { tension: 0.9 })  // tighter spring, more pronounced dispersion chirp

| Param | Default | | |---|---|---| | decay | 0.6 | 0..1 — loop feedback (tail length) | | tension | 0.5 | 0..1 — allpass dispersion coefficient (spring "tightness") | | damping | 0.4 | 0..1 — high-frequency loss in the loop | | mix | 0.35 | 0..1 — wet/dry blend | | fs | 44100 | sample rate; delay lengths scale to it |

Mutates data in place and returns it. Fresh loop/allpass state is allocated per call — no state carries across calls, reprocess the whole buffer each time.

Use when: guitar-amp/vintage spring-tank character, transient "boing". Not for: smooth room/plate tails (the dispersion coloration is the point — use freeverb/dattorro for smooth) or stereo width (mono only).

Part of the @audio/reverb family.

MIT © audiojs