Thing is even if the video isn't in HD if the sound was recorded at like 44.1khz it will sound better, so I was trying it with some of my videos.
http://youtube.com/watch?v=GaOI6MQlZSA
then adding the &fmt=18
http://youtube.com/watch?v=GaOI6MQlZSA&fmt=18
Anyway, picture looks the same, which isn't important, but I thought it sounded a lot clearer. Especially once you get at least 30 seconds in and to things like the hi-hats etc...
Gonna go check out some other vids with good music...