Merge pull request #806 from Bubobubobubobubo/noises

New noise type: "crackle"

packages/core/controls.mjs

@@ -1214,6 +1214,16 @@ const generic_params = [
    * @name waveloss
    */
   ['waveloss'],
+  /*
+   * Noise crackle density
+   *
+   * @name density
+   * @param {number | Pattern} density between 0 and x
+   * @example
+   * s("crackle*4").density("<0.01 0.04 0.2 0.5>".slow(4))
+   *
+   */
+  ['density'],
   // TODO: midi effects?
   ['dur'],
   // ['modwheel'],

packages/superdough/noise.mjs

@@ -4,7 +4,7 @@ import { getAudioContext } from './superdough.mjs';
 let noiseCache = {};
 
 // lazy generates noise buffers and keeps them forever
-function getNoiseBuffer(type) {
+function getNoiseBuffer(type, density) {
   const ac = getAudioContext();
   if (noiseCache[type]) {
     return noiseCache[type];
@@ -34,17 +34,26 @@ function getNoiseBuffer(type) {
       output[i] = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
       output[i] *= 0.11;
       b6 = white * 0.115926;
+    } else if (type === 'crackle') {
+      const probability = density * 0.01;
+      if (Math.random() < probability) {
+        output[i] = Math.random() * 2 - 1;
+      } else {
+        output[i] = 0;
+      }
     }
   }
-  noiseCache[type] = noiseBuffer;
+
+  // Prevent caching to randomize crackles
+  if (type !== 'crackle') noiseCache[type] = noiseBuffer;
   return noiseBuffer;
 }
 
 // expects one of noises as type
-export function getNoiseOscillator(type = 'white', t) {
+export function getNoiseOscillator(type = 'white', t, density = 0.02) {
   const ac = getAudioContext();
   const o = ac.createBufferSource();
-  o.buffer = getNoiseBuffer(type);
+  o.buffer = getNoiseBuffer(type, density);
   o.loop = true;
   o.start(t);
   return {

packages/superdough/superdough.mjs

@@ -241,6 +241,7 @@ export const superdough = async (value, deadline, hapDuration) => {
     source,
     gain = 0.8,
     postgain = 1,
+    density = 0.03,
     // filters
     ftype = '12db',
     fanchor = 0.5,

packages/superdough/synth.mjs

@@ -22,7 +22,7 @@ const fm = (osc, harmonicityRatio, modulationIndex, wave = 'sine') => {
 };
 
 const waveforms = ['sine', 'square', 'triangle', 'sawtooth'];
-const noises = ['pink', 'white', 'brown'];
+const noises = ['pink', 'white', 'brown', 'crackle'];
 
 export function registerSynthSounds() {
   [...waveforms, ...noises].forEach((s) => {
@@ -36,7 +36,8 @@ export function registerSynthSounds() {
         if (waveforms.includes(s)) {
           sound = getOscillator(s, t, value);
         } else {
-          sound = getNoiseOscillator(s, t);
+          let { density } = value;
+          sound = getNoiseOscillator(s, t, density);
         }
 
         let { node: o, stop, triggerRelease } = sound;

website/src/pages/learn/synths.mdx

@@ -42,6 +42,10 @@ Some amount of pink noise can also be added to any oscillator by using the `nois
 
 <MiniRepl client:idle tune={`note("c3").noise("<0.1 0.25 0.5>").scope()`} />
 
+You can also use the `crackle` type to play some subtle noise crackles. You can control noise amount by using the `density` parameter:
+
+<MiniRepl client:idle tune={`s("crackle*4").density("<0.01 0.04 0.2 0.5>".slow(4)).scope()`} />
+
 ### Additive Synthesis
 
 To tame the harsh sound of the basic waveforms, we can set the `n` control to limit the overtones of the waveform: