Left, Right sound Channels in Flash

Posted on 2008-06-16
Last Modified: 2013-11-11
I need an ActionScript that would  trigger sounds from different channels, for example, I want sound1 to be triggered from the Left Channel and sound2 to be triggered from the Right channel.
Question by:mjmusa
  • 3
LVL 42

Expert Comment

by:Rob Jurd, EE MVE
Comment Utility
using the SoundTransform class you can control the channels of the sound.  you will need to setup a SoundTransform instance for every sound you want to play and mix
LVL 42

Expert Comment

by:Rob Jurd, EE MVE
Comment Utility
Here is an example from the Adobe CS3 Reference:
package {

    import flash.display.Sprite;

    import flash.display.StageAlign;

    import flash.display.StageScaleMode;






    import flash.utils.Timer;

    public class SoundTransformExample extends Sprite {

        private var url:String = "MySound.mp3";

        private var soundFactory:Sound;

        private var channel:SoundChannel;

        private var positionTimer:Timer;

        public function SoundTransformExample() {

            stage.align = StageAlign.TOP_LEFT;

            stage.scaleMode = StageScaleMode.NO_SCALE;

            var request:URLRequest = new URLRequest(url);

            soundFactory = new Sound();

            soundFactory.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler);


            channel =;

            stage.addEventListener(MouseEvent.MOUSE_MOVE, mouseMoveHandler);


        private function ioErrorHandler(event:Event):void {

            trace("ioErrorHandler: " + event);


        private function setPan(pan:Number):void {

            trace("setPan: " + pan.toFixed(2));

            var transform:SoundTransform = channel.soundTransform;

            transform.pan = pan;

            channel.soundTransform = transform;


        private function setVolume(volume:Number):void {

            trace("setVolume: " + volume.toFixed(2));

            var transform:SoundTransform = channel.soundTransform;

            transform.volume = volume;

            channel.soundTransform = transform;


        private function mouseMoveHandler(event:MouseEvent):void {

            var halfStage:uint = Math.floor(stage.stageWidth / 2);

            var xPos:uint = event.stageX;

            var yPos:uint = event.stageY;

            var value:Number;

            var pan:Number;

            if (xPos > halfStage) {

                value = xPos / halfStage;

                pan = value - 1;

            } else if (xPos < halfStage) {

                value = (xPos - halfStage) / halfStage;

                pan = value;

            } else {

                pan = 0;


            if(pan > 1) pan = 0;

            var volume:Number = 1 - (yPos / stage.stageHeight);







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LVL 12

Accepted Solution

SamuelRostol earned 350 total points
Comment Utility
I've taken the liberty to create a quick-and-dirty example just to show you JUST what's needed to pan a sound. Hopefully you'll get the idea. I've used mostly the same variable-names as tagit to cause as little comfusion as possible.


I've attached both the code, and an example. Just remove the .txt-extension from both files to be able to run them as usual :)

Good luck!

// Have the file "sound.mp3" in same folder as swf

// Load the sound

var url:String = "sound.mp3";

var soundFactory:Sound = new Sound();

var request:URLRequest = new URLRequest(url);


// Play the sound

var channel:SoundChannel =;

// Pan the sound

var sTransform:SoundTransform = channel.soundTransform;

sTransform.pan = -1; // 1 = left speaker, -1 = right speaker, 0 = both

channel.soundTransform = sTransform;

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LVL 42

Expert Comment

by:Rob Jurd, EE MVE
Comment Utility
Great example Samuel :)

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