Use library sounds in ActionScript 3

Export a sound from the Flash library with an ActionScript linkage class, then instantiate that class like any other Sound. Keep the class name separate from the channel returned by play: the sound describes the asset, while the channel represents one playback instance.

Use a SoundTransform to set volume and stereo balance. A mixer can give music and effects separate controls, and short feedback sounds should have a concurrency limit so rapid events do not become a wall of noise.

When leaving a scene, stop channels that belong to it. Decide whether background music survives a level change, and ensure muting works before the first sound is triggered.

Try the idea

var effect:Sound = new JumpSound();
var channel:SoundChannel = effect.play();
if (channel) {
  channel.soundTransform = new SoundTransform(0.6);
}