@cod3gen/audiofilters

Audio filter design utilities (biquad PEQ/shelves, LP/HP crossover families, RIAA) for Node.js.

- Parametric and shelving EQ (biquad)
- Butterworth, Bessel, Linkwitz–Riley LP/HP crossovers (6–48 dB/oct)
- RIAA equalization (standard/inverse) with optional DC block
- Alias-based generator for ergonomic usage: generateCoeff(alias, data)

Install

``sh
npm install @cod3gen/audiofilters
`

Usage

`js
import { AudioFilters } from '@cod3gen/audiofilters';

const af = new AudioFilters();

// 1) Biquad: peaking EQ
const peq = af.generateCoeff('peq', { gain: 3, fc: 1000, Q: 1, fs: 48000 });

// 2) Crossover: LR24 low-pass at 2k
const lr24lp = af.generateCoeff('lr24', { mode: 'lowpass', fc: 2000, fs: 48000 });

// 3) RIAA
const riaa = af.generateCoeff('riaa', { sample_rate: 48000, dc_block: true });
`

API

- FilterDesigns: metadata for crossover designs (family, order, slope, sections, aliases)
- filterDesign: numeric ids per design (for compatibility)
- filterLength: number of biquad sections per design
- bqFilterDesign: numeric ids for biquad response types
- class AudioFilters:
- defaultCoefficients() → unity biquad
- makeParametricEQ(...), makeLowShelv(...), makeHighShelv(...), makeAllpass(...)
- makeHighPass(designId, fc, fs, bypass?), makeLowPass(designId, fc, fs, bypass?)
- makeRIAAEqualization(opts)
- generateCoeff(alias, data) → alias router (biquad/crossover/RIAA)

Build

`sh
npm run build
`

Demo

`sh
npm run demo
`

Publish

- GitHub: push this folder as a repo/package
- npm: bump version, then npm publish --access public`

License

MIT