Sonic can run faster than the speed of sound, but which speed of sound is he faster than, since it can range anywhere from500mph to 2000mph?
I don't think the creators of Sonic the Hedgehog were thinking about different kinds of speed of sound. It doesn't really matter, though. He goes faster than at least one of them.
It's a cartoon/game. Pick whichever one you want.
I mean if the speed of sound can travel 2000mph and hes faster then sound then it makes sense that he can run faster then 2000mph
https://www.youtube.com/watch?v=ZYFpAeqaCrw&feature=youtube_gdata_player so far I believe this would be the best answer and it also goes through some other interesting questions you might have about Sonic when he's running