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    index.js conga.js cowbell.js hihat.js kick.js mini.js monosynth.js pluck.js snare.js tom.js tonewheel.js delay.js feedback-comb-filter.js filter.js gain-envelope.js gain.js lfo.js mono-buffer.js noise.js osc-bank.js osc.js pulse.js sample.js soft-clipper.js source.js vca.js vcf.js vco.js wave-shaper.js synth.js

  • tonewheel.js

  • ¶

    Tonewheel aka clonewheel synth

    import { instrument } from "../synth"
import Gain from "../kit/gain"
import Pulse from "../kit/pulse"
import GainEnvelope from "../kit/gain-envelope"
import OscBank from "../kit/osc-bank"
  • ¶

    This will be an simple model of a Hammond B3 organ. Reproducing the sound of that instrument is a complex task, I”ll only recreate a very simplified model. Any sonic resemblance with the original is just coincidence.

  • ¶

    References

  • ¶

    https://teichman.org/blog/2011/05/roto.html http://electricdruid.net/technical-aspects-of-the-hammond-organ/ http://www.dairiki.org/HammondWiki/OriginalHammondLeslieFaq http://www.stefanv.com/electronics/hammond_drawbar_science.html

  • ¶

    http://electricdruid.net/technical-aspects-of-the-hammond-organ/

    const RATIOS = [0.5, 1.498823530, 1, 2, 2.997647060, 4, 5.040941178, 5.995294120, 8]
  • ¶

    Drawbars

  • ¶

    The sound on a tonewheel Hammond organ is varied through the manipulation of drawbars. A drawbar is a metal slider that controls the volume of a particular sound component, in a similar way to a fader on an audio mixing board. As a drawbar is incrementally pulled out, it increases the volume of its sound. When pushed all the way in, the volume is decreased to zero

  • ¶

    Presets

    http://www.dairiki.org/HammondWiki/PopularDrawbarRegistrations

    const PRESETS = {
  gospel: toState("88 8000 008"),
  blues: toState("88 8800 000"),
  bluesB: toState("88 5324 588"),
  booker: toState("88 8630 000"),
  onions: toState("80 8800 008"),
  smith: toState("88 8000 000"),
  mcgriff: toState("86 8600 006"),
  errol: toState("80 0008 888"),
  genesis: toState("33 6866 330"),
}
  • ¶

    Given a preset, return a state fragment

    function toState (preset) {
  if (preset) {
    const norm = (preset.replace(/[^012345678]/g, "") + "000000000").slice(0, 9)
    const gains = norm.split("").map((n) => Math.abs(+n / 8))
    return {
      bank: { gains }
    }
  }
}
  • ¶

    Instrument

    export default function Tonewheel (ac, preset) {
  preset = preset ? toState(preset) : PRESETS["smith"]
  const state = Object.assign({}, Tonewheel.defaults, preset)
  • ¶

    Tonewheel instrument output

      const tw = instrument(ac, {
    bank: [OscBank(ac, RATIOS), "envelope"],
    envelope: [GainEnvelope, "amp"],
    click: [Pulse, "output"],
    amp: [Gain, "output"],
  }).update(state)

  tw.setPreset = (preset, time) => {
    const newState = PRESETS[preset] || toState(preset)
    tw.update(newState)
  }
  • ¶

    API

      tw.trigger = (freq, time, dur) => {
    tw.bank.update(freq, time)
    tw.envelope.trigger(time, dur)
    return tw
  }

  return tw
}
Tonewheel.defaults = {
  bank: {
    types: ["sine"],
  },
  amp: {
    gain: 0.8,
  }
}