gibberish-dsp/js/filters/allpass.js

Gibberish is designed to be an optimized API for audio synthesis using per-sample techniques.

let g = require( 'genish.js' )
 
// constructor for schroeder allpass filters
let allPass = function( _input, length=500, feedback=.5 ) {
  let index  = g.counter( 1,0,length ),
      buffer = g.data( length ),
      bufferSample = g.peek( buffer, index, { interp:'none', mode:'samples' }),
      out = g.memo( g.add( g.mul( -1, _input), bufferSample ) )
                
  g.poke( buffer, g.add( _input, g.mul( bufferSample, feedback ) ), index )
 
  return out
}

module.exports = allPass