AudioBufferSourceNode: свойство detune

const audioCtx = new AudioContext();

const channelCount = 2;
const frameCount = audioCtx.sampleRate * 2.0; // 2 seconds

const myArrayBuffer = audioCtx.createBuffer(
  channelCount,
  frameCount,
  audioCtx.sampleRate,
);

for (let channel = 0; channel < channelCount; channel++) {
  const nowBuffering = myArrayBuffer.getChannelData(channel);
  for (let i = 0; i < frameCount; i++) {
    nowBuffering[i] = Math.random() * 2 - 1;
  }
}

const source = audioCtx.createBufferSource();
source.buffer = myArrayBuffer;
source.connect(audioCtx.destination);
source.detune.value = 100; // value in cents
source.start();