如何使用Javascript播放特定频率? [英] How to play a specific frequency with Javascript?

问题描述

我想要一个像这样的函数:

I want a function that works like this:

playSound(345, 1000)

将以345 hz的音调播放1000毫秒.在JavaScript中最简单的方法是什么?我不介意它是使用样本(也许是罪孽之波，还是钢琴)，还是使用计算机的硬件来生成声音.

Which would play a tone of 345 hz for 1000 milliseconds. What is the simplest way to achieve this in JavaScript? I don't mind if it uses a sample (maybe of a sin wave, or piano), or uses the computer's hardware to generate the sound.

推荐答案

正如注释中已指出的那样，方法是通过

As already pointed out in the comments, the way to do it is through the OscillatorNode.

// create web audio api context
var audioCtx = new(window.AudioContext || window.webkitAudioContext)();

function playNote(frequency, duration) {
  // create Oscillator node
  var oscillator = audioCtx.createOscillator();

  oscillator.type = 'square';
  oscillator.frequency.value = frequency; // value in hertz
  oscillator.connect(audioCtx.destination);
  oscillator.start();

  setTimeout(
    function() {
      oscillator.stop();
      playMelody();
    }, duration);
}

function playMelody() {
  if (notes.length > 0) {
    note = notes.pop();
    playNote(note[0], 1000 * 256 / (note[1] * tempo));
  }
}

notes = [
  [659, 4],
  [659, 4],
  [659, 4],
  [523, 8],
  [0, 16],
  [783, 16],
  [659, 4],
  [523, 8],
  [0, 16],
  [783, 16],
  [659, 4],
  [0, 4],
  [987, 4],
  [987, 4],
  [987, 4],
  [1046, 8],
  [0, 16],
  [783, 16],
  [622, 4],
  [523, 8],
  [0, 16],
  [783, 16],
  [659, 4]
];

notes.reverse();
tempo = 100;

playMelody();

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