public void changeVolume(VolumeControlGUI vc,int newVolume)
	{
		if(vc != null)
		{
			for(int i=0; i<list.capacity(); i++)
			{
				//only change the volume, if this slider does not changed the volume
				if(list.get(i) != vc)
				{
					list.get(i).setVolume(newVolume);
				}
				
				//finally set it in the sound system
				mainGui.setVolume(newVolume);
			}
		}
	}