Q: How do you promote classical music to people who say they don't know anything about it?
A: Classical is not all the same. Start listening to all kinds of composers from all periods. Don't worry about target audiences. Don't worry about your own limitations either.
Classical doesn't need to be made sexier. If you're trying to push some cheesy crap like "classical for headbangers", you are completely on the wrong path.
We have had things like symphonic metal for decades. A lot of these bands aren't really changing anything. Usually they're just writing metal music, not classical.
As a listener, expand your horizons. As a composer, write the music you can't find.
