|Rap meets metal; the mashup was also racial, with rap's white aud small until this|
From the point that hiphop began emerging in the late 70s (broken big by Run DMC in the mid-80s, and really taken to stratospheric heights once white rappers emerged from Vanilla Ice to Eminem), the concept of genre in music has been problematic. Hiphop is a genre but one defined by its used of all other existing genres.
The concept of the mash-up emerged as a specific variant of this: literally blending two (or more) tracks which the mixer thinks work well together - perhaps the most famous example being Jay-Z's Black Album: remixed by Danger Mouse, weaving in Beatles tracks, to create The Grey Album.
A mashup or bootleg (also mesh, mash up, mash-up, blend and bastard pop/rock) is a song or composition created by blending two or more pre-recorded songs, usually by overlaying the vocal track of one song seamlessly over the instrumental track of another. To the extent that such works are 'transformative' of original content, they may find protection from copyright claims under the "fair use" doctrine of copyright law [wiki]
Nu-metal is an interesting example - bursting into the limelight in the mid-90s, and taking up the commercial status lost by grunge as it faded away following Cobain's death, it combined metal and hiphop. The pioneer bands (Korn, Deftones, Limp Bizkit) were controversial within the metal fanbase, the hybridity seeing many genre fans rejecting them as inauthentic; not actually metal.
Its time as a predominant musical force was quite brief ... but currently enjoying a resurgence as Limp Bizkit return.
Moreover, Korn have just announced a dubstep-influenced album (with Skrillex): http://loudwire.com/korn-frontman-discusses-new-dubstep-album-current-state-of-rock/ The concept of metal is stretched to its limit here ... and this is hot on the heels of Metallica's album with Lou Reed (leading some to talk of Loutallica!)
But nu-metal is far from unique. Beatallica are a band who fuse Metallica-style singing and playing with Beatles tracks; Dread Zeppelin fuse reggae, Elvis and Led Zeppelin; Apocalyptica play orchestral, classical music renderings of thrash metal bands (I particularly enjoy their version of Slayer's South of Heaven; a brutal album whose power still comes through even when riffs are cello rather than guitar based!)
We've looked at the work of Andy Rehnfeldt (here's his website; YT channel; Facebook; MySpace; and a random hater!)
Tape-swapping, using the post, was a key means of how emerging genres would evolve and grow back in the 80s; ventures such as this wouldn't have gotten anything like the near 27m views Rehfeldt's vids have enjoyed on YouTube by Nov 2011. His shtick is simple but delivered with real elan: using original video footage, re-present a track re-recorded in an anthitetical musical style - so we get Rebecca Black's Friday as death metal (big improvement there of course!) and some Katy Perry aural atrocity rendered listenable as death metal, but equally Slayer's crushingly heavy Angel of Death as Radio Disney, and Metallica's Enter Sandman as smooth jazz! Have a look and see if he's covered any bands within your genre...
Even Wonderful World gets the death metal treatment...
|Kutiman mashes up vids he's found on YouTube|
|His own site, http://thru-you.com/|
Actually mashing video, we have the VJ artist Kutiman, who's had 6.3m hits himself. He runs his own site as well as the YouTube channel; one example of his work follows below