Welcome back to our series about Flash Audio. Now we will deal with some more complicated stuff, stereo and mono sounds. To accomplish that, I have to instroduce you to the Transform object in Flash. Sounds complicated, but it’s not that complicated. In ActionScript, you have the “Object” DataType. Like this:

//define an object in ActionScript
var myObject:Object = new Object();

//add properties
myObject.name = “SomeBody”;
myObject.surname = “SomeSurname”;

Now you have an object with the properties name and surname.

But what has this to to with the sound? Here is the answer. The sound in Flash is transformed eg. divided into speakers. When the stereo sound is on (by default it is stereo), then the right speaker has the percentage of 100 and the left too. In ActionScript, it is written like this:

ll = 100
lr = 0
rr = 100
rl = 0

What the heck? It’s not that complicated. Ll stands for Left input on left speaker. Lr stands for left input on right speaker. Rr for right input on right speaker and rl for right input on left speaker. The variables can have values from 0 – 100. As you suggest, you adjust the values to create mono or stereo sound.

//sample mono on left speaker
ll = 100
lr = 100
rr = 0
rl = 0

//sample mono on right speaker
ll = 0
lr = 0
rr = 100
rl = 100

So now that you understand the show transform object you have to know how to apply this to the sound object. Assume you have a track in your Flash document library with the linkage ID set to “myTrack”. The code would look similar to this:

//create the new sound object
var mySound:Sound = new Sound();

//attach the track from the library
mySound.attachAudio(“myTrack”);

//create the mono sound transform object for the right speaker
var monoSoundRight:Object = new Object();
monoSoundRight.ll = 0
monoSoundRight.lr = 0
monoSoundRight.rr = 100
monoSoundRight.rl = 100

//apply it to the sound object
mySound.setTransform(monoSoundRight);

So, it is now very easy to create a Flash movie with buttons that switch between left and right speakers. Here is how it is done:

Open a new Flash document. Import a new sound into the library (Image 1).

Stereo audio in Flash

Give it the linkage ID “myTrack” (Image 2).

flash stero audio tutorial

Create two layers on the main timeline: “Actions” and “Content”. Make sure the “Actions” layer is above the “Content” layer (Image 3).

stero audio in flash

Create two buttons for the right and the left speaker. Place them on the stage and give the left button the instance name “left_btn” and “right_btn” to the right button (image 4).

flash audio tutorial

Paste the following code into the first frame of the Actions folder:

var mySound:Sound = new Sound();
mySound.attachSound(“myTrack”);

mySound.start(0, 50);

right_btn.onRelease = function () {
mySound.setTransform(rightMonoSound);
}

left_btn.onRelease = function () {
mySound.setTransform(leftMonoSound);
}

var leftMonoSound:Object = new Object();
leftMonoSound.ll = 100;
leftMonoSound.lr = 100;
leftMonoSound.rr = 0;
leftMonoSound.rl = 0;

var rightMonoSound:Object = new Object();
rightMonoSound.ll = 0;
rightMonoSound.lr = 0;
rightMonoSound.rr = 100;
rightMonoSound.rl = 100;

var stereoSound:Object = new Object();
rightMonoSound.ll = 100;
rightMonoSound.lr = 0;
rightMonoSound.rr = 100;
rightMonoSound.rl = 0;

The first thing you have to do of course is to start Flash. In this tutorial I use Flash 8 Professional, but the tutorial here can be applied to Flash MX 2004 or Flash MX. Go to File -> Import -> Import to Library….

A dialog box appears asking you to choose a file from your hard drive.

Because you need only sound formats and the rest can be ignored, the next thing you have to do is to filter the sound files using the “Files of Type” drop down menu and selecting “All Sound Formats”.

Select an MP3 (or other sound format) on and click “Open”.

The track appears now in the Library of the Flash Movie. You can open the library through Window -> Library. Open the library to see the imported MP3 file.

As you can see, you can preview the file in the library and perform some optimization in the settings. But that’s not the focus of this tutorial, we just want to add some sound to our movie. Go to the timeline of the movie and add an additional layer (Insert -> Timeline -> Layer).

Now you have 2 layers on your timeline. Rename the upper layer “Sound”, the layer below rename to “Content”. That’s it. Your timeline should now look like on image 7.

Select the first frame on the layer “Sound” and open the first properties panel (Window -> Properties). In the panel, find the “Sound” drop down panel and select the imported sound file.

You can now test the movie clicking on Control -> Test Movie or pressing Ctrl + Enter.