EnhancedSound is a sub class of built-in Sound class, which extends Sound with some extra properties and methods.
The properties and the methods of Sound are available as they are, with this EnhancedSound as well.

Properties added (All optional)

file

defaultVolume

Used for the methods 'fadeOut' and 'fadeIn'

dontOverLap

A boolean value which specifies whether the sound can be played overlapping itself when it's already playing. If true, it stops the previous play before it starts.

offset

loopCount

xPosPan

An x coordinate number value which sets its panning position.
i.e. Assigning 0 to xPosPan sets the pan to leftmost and Stage.Width to rightmost.

Methods added

setDefaultVolume

setDontOverlap

setOffset

setLoopCount

setXPosPan

Can be useful when you want the sound's pan to follow the mc's _x.
mySound.setXPosPan(0) is equivalent to mySound.setPan(-100).
mySound.setXPosPan(Stage.Width) is equivalent to mySound.setPan(100).

play

Equivalent to 'start' of Sound, except it supports 'dontOverlap' and switching 'file'.

fadeOut

Fades-out the sound during the time specified with the passed milliseconds value.

fadeIn

Fades-in the sound during the time specified with the passed milliseconds value.
Optionally, you can specify the file to play at this time as well.

Usage example 1

// "bell.wav" and "buzzer.wav" in the library of _level10

_level10.createEmptyMovieClip("SE_bell_mc", 1);
_level10.createEmptyMovieClip("SE_buzzer_mc", 2);

// The parameters, except the first one which specifies the timeline, are all optional.

_global.SE_bell = new EnhancedSound(_level10.SE_bell_mc, "bell.wav");
_global.SE_buzzer = new EnhancedSound(_level10.SE_buzzer_mc, "buzzer.wav", 70, true, 0.008, 0, Stage.Width*0.7);

SE_bell.play();
SE_buzzer.play();

Usage example 2

// "song1.wav" and "song2.wav" in the library of _level1

_global.BGM1 = new EnhancedSound(_level1, null, 50, true, 0, 9999);

BGM1.play("song1.wav");
// You may switch 'file' to another at a later time
BGM1.play("song2.wav");

// Also you may do something like this to cross-fade two BGMs.

// "song3.wav" in the library of _level2
_global.BGM2 = new EnhancedSound(_level2, "song3.wav", 50, true, 0, 9999);

BGM1.fadeOut(3000);
BGM2.fadeIn(3000);