I've been watching youtube, Hulu, veoh, cbs, and other internet tv channels through a macbook hooked up to an hdtv. Why is the sound so low? When I watch a video on a hard drive I always use VLC because you can crank the volume to 350%!!!!!! It REALLY helps. Usually 250% is "normal" sounding on the tv. Is there a way to get this done at a system level when hooked up to the headphone jack?