Deprecated
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 compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
The deprecated dopplerFactor
property of the AudioListener
interface is a double value representing the amount of pitch shift to use when rendering a doppler effect.
The dopplerFactor
property's default value is 1
, which is a sensible default for most situations.
Syntax
var audioCtx = new AudioContext(); var myListener = audioCtx.listener; myListener.dopplerFactor = 1;
Value
A double indicating the doppler effect's pitch shift value. The value is 1 by default.
Example
In the following example, you can see an example of how the createPanner()
method, 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()
function.
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; }
Note: 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.
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
dopplerFactor | Chrome No support 14 — 56 | Edge No support 12 — 79 | Firefox No support 25 — 63 | IE No support No | Opera No support 15 — 43 | Safari Full support 6 | WebView Android No support ? — 56 | Chrome Android No support 18 — 56 | Firefox Android No support 26 — 63 | Opera Android No support 14 — 43 | Safari iOS ? | Samsung Internet Android No support 1.0 — 6.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Deprecated. Not for use in new websites.
- Deprecated. Not for use in new websites.