[TheOtherHobbes]

Common Music is a much more mature and comprehensive project and uses Scheme - close to Racket - and/or its own DSL. There's also the option to do synthesis.

http://commonmusic.sourceforge.net/

There's also Overtone for Clojure fans, which also does synthesis:

http://overtone.github.io/

And Impromptu, PD, Csound, Supercollider... and Max if you want something commercial.

And projects with much higher levels of abstraction like Rubato Composer.

(And many others, in fact.)

I guess there's no reason not to make something like Alda as a simple student exercise. But compared to the alternatives, it isn't any more powerful than that.