Tracy makes that noise every time he thinks he is fouled, but don't he know the refs don't listen to that "ahhhhhhhhhhhhhh?"
Yeah, some of the other players do it now too. Rafer = "haaaaaaaaaaayyyyyyyyyyy", Yao = "ooooooyyyyyyyy". It's pretty funny. And I think the refs used to go for it a bit more, but they do it so much now that they quit listening as much.