We usually use wave 'to' someone to say 'hello'. We wave 'at' someone to say hello, goodbye or to attract their attention. So in your sentence you could probably use either 'to' or 'at' depending on the reason the audience is waving.

at wave at = say hello; goodbye; acknowledge someone is there wave to = give a signal to go and do something

I think either would work, but "to" sounds better. It sounds more polite. When someone says, "You're speaking at me, not to me," it means you're not interested in the other person. Also, it's spelled "Artist."