As the guy who wrote the first bits of the Rdio code in question, it seems worth mentioning that the part in question has nothing to do with Backbone, or Ember, or anything else. That code is a cleanup function on an object that helps to abstract HTML5 <audio> vs our Flash fallback.

No matter what framework you are using, if you are solving the problems that we are solving, you are going to end up with that code.

Now, that said, I agree that learning all of the frameworks out there is advantageous, but you can't assume that the code in the blog post is indicative of anything having to do with Backbone or any other framework.