The refDistance
property of the PannerNode
interface is a double value representing the reference distance for reducing volume as the audio source moves further from the listener – i.e. the distance at which the volume reduction starts taking effect. This value is used by all distance models.
The refDistance
property's default value is 1
.
Syntax
var audioCtx = new AudioContext(); var panner = audioCtx.createPanner(); panner.refDistance = 1;
Value
A non-negative number. If the value is set to less than 0, a RangeError
is thrown.
Exceptions
RangeError
- The property has been given a value that is outside the accepted range.
Example
This example demonstrates how different values of refDistance
affect how the volume of a sound decays as it moves away from the listener. Unlike rolloffFactor
, changing this value also delays the volume decay until the sound moves past the reference point.
const context = new AudioContext(); // all our test tones will last this many seconds const NOTE_LENGTH = 6; // this is how far we'll move the sound const Z_DISTANCE = 20; // this function creates a graph for the test tone with a given refDistance // and schedules it to move away from the listener along the Z (depth-wise) axis // at the given start time, resulting in a decrease in volume (decay) const scheduleTestTone = (refDistance, startTime) => { const osc = new OscillatorNode(context); const panner = new PannerNode(context); panner.refDistance = refDistance; // set the initial Z position, then schedule the ramp panner.positionZ.setValueAtTime(0, startTime); panner.positionZ.linearRampToValueAtTime(Z_DISTANCE, startTime + NOTE_LENGTH); osc.connect(panner) .connect(context.destination); osc.start(startTime); osc.stop(startTime + NOTE_LENGTH); }; // this tone should decay immediately and fairly quickly scheduleTestTone(1, context.currentTime); // this tone should decay slower and later than the previous one scheduleTestTone(4, context.currentTime + NOTE_LENGTH); // this tone should decay only slightly, and only start decaying fairly late scheduleTestTone(7, context.currentTime + NOTE_LENGTH * 2);
After running this code, the resulting waveforms should look something like this:
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'refDistance' in that specification. |
Working Draft |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
refDistance | Chrome Full support 14 | Edge Full support 12 | Firefox Full support 25 | IE No support No | Opera Full support 15 | Safari Full support 6 | WebView Android Full support Yes | Chrome Android Full support 18 | Firefox Android Full support 26 | Opera Android Full support 14 | Safari iOS ? | Samsung Internet Android Full support 1.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown