Who does Hebdige say has a major affect on defining subcultures to the public?

The media has a strong influence over people when it comes to understanding subcultures. For example, if within a subculture its members have the reputation of being tough and violent, yet the only thing the public sees on TV is snapshots of them saving kittens from a tree, it would be hard to convince the public of their self-painted "bad boy" picture.