I believe, there’s a limit to how much you can modify and tweak your raw material, how far you can take it, and still be able to call your work “Mashup”. Judging by common sense, I would say that as long as one does not modify the raw materials as much as they bear no resemblance to their original, the outcome can still be titled “Mashup” and not contradict the definition.
I do not believe that DJ Danger Mouse remains loyal to The Beatles’s unique voice and melody enough for the Grey album to be called a legitimate “Mashup”. Despite the fact that personally I enjoyed listening to this album, there were many points here and there that The Beatles’s sounds could be replaced with other musical bits from other artists and it would not change a thing.
In my opinion, the artist should choose her raw materials carefully enough for them to be as noninterchangeable as possible. That is mostly not the case about “The Grey Album”
However, I do like Jay-Z’s A Capella release. It is an open attitude that encourages sharing with an open source spirit.
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