PannerNode.maxDistance
The maxDistance
property of the PannerNode
interface is a double value representing the maximum distance between the audio source and the listener, after which the volume is not reduced any further. This value is used only by the linear
distance model.
The maxDistance
property's default value is 10000
.
Syntax
var audioCtx = new AudioContext(); var panner = audioCtx.createPanner(); panner.maxDistance = 10000;
Value
A double.
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.
This example also recreates the doppler effect — when movement is initiated in any direction, velocity is set on the panner (again, see positionPanner()
), which is cancelled out onmouseup
.
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!
// define Web Audio API objects 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; panner.setOrientation(1,0,0); var listener = audioCtx.listener; listener.dopplerFactor = 1; listener.speedOfSound = 343.3; listener.setOrientation(0,0,-1,0,1,0); var source; var boomBox = document.querySelector('.boom-box'); // set up listener and panner position information var WIDTH = window.innerWidth; var HEIGHT = window.innerHeight; var xPos = WIDTH/2; var yPos = HEIGHT/2; var zPos = 295; // Only x and z velocity needed, as the listener only moves left and right and in and out in this example. Never up and down. var xVel = 0; var zVel = 0; leftBound = (-xPos) + 50; rightBound = xPos - 50; xIterator = WIDTH/150; // listener will always be in the same place for this demo 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() { panner.setPosition(xPos,yPos,zPos); panner.setVelocity(xVel,0,zVel); pannerData.innerHTML = 'Panner data: X ' + xPos + ' Y ' + yPos + ' Z ' + zPos; } // controls to move left and right past the boom box // and zoom in and out // only right movement code shown in this listing to save space // look at the source code for full listing var leftButton = document.querySelector('.left'); var rightButton = document.querySelector('.right'); var zoomInButton = document.querySelector('.zoom-in'); var zoomOutButton = document.querySelector('.zoom-out'); var boomX = 0; var boomY = 0; var boomZoom = 0.25; var zoomInLoop; var zoomOutLoop function moveRight() { boomX += -xIterator; xPos += -0.066; xVel = 17; if(boomX <= leftBound) { boomX = leftBound; xPos = (WIDTH/2) - 5; } boomBox.style.transform = "translate(" + boomX + "px , " + boomY + "px) scale(" + boomZoom + ")"; positionPanner(); rightLoop = requestAnimationFrame(moveRight); return rightLoop; } rightButton.onmousedown = moveRight; rightButton.onmouseup = function () { window.cancelAnimationFrame(rightLoop); xVel = 0; panner.setVelocity(0,0,0); }
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 fiddly maths involved, but you will soon get used to it with a bit of experimentation.
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'maxDistance' in that specification. |
Working Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 10.0webkit | 25.0 (25.0) | Not supported | 15.0webkit 22 (unprefixed) |
6.0webkit |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | ? | 26.0 | 1.2 | ? | ? | ? | 33.0 |
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/pannernode/maxdistance