There is no onComplete event that fires when the sound has been loaded, so we must check the sndProgressHandler
#Flash actionscript 3.0 pass sound to method code
The following example code have added 2 event listeners to aid in monitoring the load progress of the file and have also added a function called playSound():void that will be called when the file has been completely loaded in. But let us concentrate on the direct sound Classes. There are some other Classes without which we couldn’t use sound, such as the URLRequest class, which we use to load the sound file. The following picture demonstrates the cooperation of these classes