PannerNode.rolloffFactor
The rolloffFactor
property of the PannerNode
interface is a double value describing how quickly the volume is reduced as the source moves away from the listener. This value is used by all distance models.The rolloffFactor
property's default value is 1
.
Value
A number whose range depends on the distanceModel
of the panner as follows (negative values are not allowed):
- "
linear
" -
The range is 0 to 1.
- "
inverse
" -
The range is 0 to
Infinity
. - "
exponential
" -
The range is 0 to
Infinity
.
Exceptions
RangeError
-
The property has been given a value that is outside the accepted range.
Examples
This example demonstrates how different rolloffFactor
values affect how the volume of the test tone decreases with increasing distance from the listener:
const context = new AudioContext();
// all our test tones will last this many seconds
const NOTE_LENGTH = 4;
// 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 rolloffFactor
// 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 = (rolloffFactor, startTime) => {
const osc = new OscillatorNode(context);
const panner = new PannerNode(context);
panner.rolloffFactor = rolloffFactor;
// 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 fairly quickly
scheduleTestTone(1, context.currentTime);
// this tone should decay slower than the previous one
scheduleTestTone(0.5, context.currentTime + NOTE_LENGTH);
// this tone should decay only slightly
scheduleTestTone(0.1, context.currentTime + NOTE_LENGTH * 2);
After running this code, the resulting waveforms should look something like this:
Specifications
Specification |
---|
Web Audio API # dom-pannernode-rollofffactor |
Browser compatibility
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