Edit Sound
Flash provides very basic and limited editing environment for sound. We can use predefined fades and sound effects. These preset effects are:
Sound envelope
Envelope lines show the volume of the sound when it plays. In order to change the sound envelope, drag the envelope handles on the envelope lines to change levels at different points in the sound. We can add envelope handles(total 8 handles).Click envelope line to add a handle. To remove a handle, drag it out of the window.
To make any change in sound drag handles up or down and check sound by pressing play button.
In the figure below, three extra handles are added. You can add maximum of 8 handles.
These three handled are repositioned to change sound effect.
Time Control
To change the start and end points of sound, drag the Time In and Time Out controls .
Effects: In frame properties dialogue box we find effects,synchronize and loops options:
When we click effects,a drop- down list appears:

None:applies no effects to the sound file.
Left Channel/Right Channel: plays sound only in the left or right channel.
Fade Left to Right/Fade Right to Left: shifts the sound from one channel to the other.
Fade In: gradually increases the amplitude of a sound over its duration.
Fade Out: gradually decreases the amplitude of a sound over its duration.
Custom lets you create your own sound effects.

Use looping to play sound repeatedly. Enter a number(4,5,6,7....) to play sound...... times.
To stop a sound:
Double-click the ending keyframe and click the Sound tab in the Frame Properties dialog box.
Choose Stop from the Synchronization drop-down list.
When you play the movie, the sound stops playing when it reaches the ending keyframe.