AudioListener.speedOfSound

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弃用
This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the 兼容性表格 at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

speedOfSound 特性为 AudioListener interface is a double value representing the speed of sound, in meters per second .

speedOfSound property's default value is 343.3 m/s and is used to calculate the doppler shift appropriate for the speed the panner is travelling at (as defined by PannerNode.setVelocity )。

注意 : Bear in mind that no propagation delay is automatically applied to a sound far from the listener.

句法

var audioCtx = new AudioContext();
var myListener = audioCtx.listener;
myListener.speedOfSound = 343.3;

值

A double.

范例

In the following example, you can see an example of how the createPanner() 方法， AudioListener and PannerNode would be used to control audio spatialisation. Generally you will define the position in 3D space that your audio listener and panner (source) occupy initially, and then update the position of one or both of these as the application is used. You might be moving a character around inside a game world for example, and wanting delivery of audio to change realistically as your character moves closer to or further away from a music player such as a stereo. In the example you can see this being controlled by the functions moveRight() , moveLeft() , etc., which set new values for the panner position via the PositionPanner() 函数。

To see a complete implementation, check out our panner-node example ( view the source code ) — this demo transports you to the 2.5D "Room of metal", where you can play a track on a boom box and then walk around the boom box to see how the sound changes!

Note how we have used some feature detection to either give the browser the newer property values (like AudioListener.forwardX ) for setting position, etc. if it supports those, or older methods (like AudioListener.setOrientation() ) if it still supports those but not the new properties.

// set up listener and panner position information
var WIDTH = window.innerWidth;
var HEIGHT = window.innerHeight;
var xPos = Math.floor(WIDTH/2);
var yPos = Math.floor(HEIGHT/2);
var zPos = 295;
// define other variables
var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext();
var panner = audioCtx.createPanner();
panner.panningModel = 'HRTF';
panner.distanceModel = 'inverse';
panner.refDistance = 1;
panner.maxDistance = 10000;
panner.rolloffFactor = 1;
panner.coneInnerAngle = 360;
panner.coneOuterAngle = 0;
panner.coneOuterGain = 0;
if(panner.orientationX) {
  panner.orientationX.setValueAtTime(1, audioCtx.currentTime);
  panner.orientationY.setValueAtTime(0, audioCtx.currentTime);
  panner.orientationZ.setValueAtTime(0, audioCtx.currentTime);
} else {
  panner.setOrientation(1,0,0);
}
var listener = audioCtx.listener;
if(listener.forwardX) {
  listener.forwardX.setValueAtTime(0, audioCtx.currentTime);
  listener.forwardY.setValueAtTime(0, audioCtx.currentTime);
  listener.forwardZ.setValueAtTime(-1, audioCtx.currentTime);
  listener.upX.setValueAtTime(0, audioCtx.currentTime);
  listener.upY.setValueAtTime(1, audioCtx.currentTime);
  listener.upZ.setValueAtTime(0, audioCtx.currentTime);
} else {
  listener.setOrientation(0,0,-1,0,1,0);
}
var source;
var play = document.querySelector('.play');
var stop = document.querySelector('.stop');
var boomBox = document.querySelector('.boom-box');
var listenerData = document.querySelector('.listener-data');
var pannerData = document.querySelector('.panner-data');
leftBound = (-xPos) + 50;
rightBound = xPos - 50;
xIterator = WIDTH/150;
// listener will always be in the same place for this demo
if(listener.positionX) {
  listener.positionX.setValueAtTime(xPos, audioCtx.currentTime);
  listener.positionY.setValueAtTime(yPos, audioCtx.currentTime);
  listener.positionZ.setValueAtTime(300, audioCtx.currentTime);
} else {
  listener.setPosition(xPos,yPos,300);
}
listenerData.innerHTML = 'Listener data: X ' + xPos + ' Y ' + yPos + ' Z ' + 300;
// panner will move as the boombox graphic moves around on the screen
function positionPanner() {
  if(panner.positionX) {
    panner.positionX.setValueAtTime(xPos, audioCtx.currentTime);
    panner.positionY.setValueAtTime(yPos, audioCtx.currentTime);
    panner.positionZ.setValueAtTime(zPos, audioCtx.currentTime);
  } else {
    panner.setPosition(xPos,yPos,zPos);
  }
  pannerData.innerHTML = 'Panner data: X ' + xPos + ' Y ' + yPos + ' Z ' + zPos;
}

注意 : In terms of working out what position values to apply to the listener and panner, to make the sound appropriate to what the visuals are doing on screen, there is quite a bit of math involved, but you will soon get used to it with a bit of experimentation.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`speedOfSound` 弃用	Chrome 不支持 14 — 56	Edge 不支持 12 — 79	Firefox 不支持 25 — 63	IE 不支持 No	Opera 不支持 15 — 43	Safari 6	WebView Android 不支持 ? — 56	Chrome Android 不支持 18 — 56	Firefox Android 不支持 26 — 63	Opera Android 不支持 14 — 43	Safari iOS ?	Samsung Internet Android 不支持 1.0 — 6.0

图例

完整支持
不支持
兼容性未知 ?
弃用。不要用于新网站。

另请参阅

使用 Web 音频 API

元数据

最后修改： Dec 24, 2019

Web 音频 API
AudioListener
特性
1. dopplerFactor
2. forwardX
3. forwardY
4. forwardZ
5. positionX
6. positionY
7. positionZ
8. speedOfSound
9. upX
10. upY
11. upZ
方法
1. setOrientation()
2. setPosition()
Related pages for Web Audio API

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句法

值

范例

浏览器兼容性

图例

另请参阅

相关话题