code: private void startMusic(float pitch, float volume, boolean loop) {
  		if (currentMusic != null) {
  			currentMusic.stop();
  			currentMusic.fireMusicSwapped(this);
  		}
  		
  		currentMusic = this;
  		if (volume < 0.0f)
  			volume = 0.0f;
  		if (volume > 1.0f)
  			volume = 1.0f;
  
  		sound.playAsMusic(pitch, volume, loop);
  		playing = true;
  		setVolume(volume);
  		if (requiredPosition != -1) {
  			setPosition(requiredPosition);
  		}
  	}
docs: play or loop the music at a given pitch and volume
  @param pitch The pitch to play the music at (1.0 = default)
  @param volume The volume to play the music at (1.0 = default)
  @param loop if false the music is played once, the music is looped otherwise