Public domain is not open source, that's not what this article is talking about. And GPL as it is makes no sense to apply to music, because then you have to re-define words like "binary" and "source" for it to even be applicable. In a legal document, which the GPL is, you just don't do that kind of shit. You have to say what you mean, or it's unenforceable. And by the time you re-defined everything, you have re-created Creative Commons in a much more verbose way and deserve to be cock-punched (or kicked in the box if that's your anatomy)
It sounds like the author has not heard of Creative Commons, but there is one mention of it ("bring together the ideas of the Creative Commons and open source to create a new, sustainable future for music"), and the article is licensed as CC. What it actually is, is someone who is unable to write a coherent thesis, mixing terms and concepts that don't make any sense together except metaphorically.
The core of the article seems to be about applying ideas that Glenn Gould put forward in 1966 to today's music. This is already taken care of by CC licensing. Kanye West, Peter Gabriel, Radiohead, and others have already allowed people to do most of this, legally.
The closest to true "open source" is Chapel Club, a band that I've never heard about and don't really care to after reading that article.
That was Nov. 2012, pretty much a year ago now. Kanye was in 2008. The example given is Open Goldberg Variations, which is Creative Commons licensed, which is different from open source (conceptually the same but the terms are different). Apparently some or all of it is now Commons Zero, basically public domain. So if there is already a name for this, and a license permitting it, what is the point of this article?
Can there be open source music? Let's all just say no, it doesn't make sense to stretch the idea of "source code" which, thanks to court cases like the SCO debacle, already have a well defined meaning (legally I mean).