The song may sound familiar at first, thanks to the unmistakable guitar riff from Nirvana's classic Smells Like Teen Spirit.
But suddenly, the recording changes course. Instead of the gravelly voice of Kurt Cobain, the smooth R&B harmonies from a Destiny's Child hit appear on top of the grunge instrumental.
As the recording moves on, it is clear that the song is neither fish nor fowl; it is a crossbreed that neither band ever intended, or even dreamed of.
It is something that, thanks to the Internet, is completely different, generally illegal and becoming explosively popular.
Songs like this one, which combine different hits without adding any original music, may represent the first significant new musical genre to be lifted out of the underground, developed and then spread, all via the Web.
The songs, called mash-ups or bootlegs, typically match the rhythm, melody and underlying spirit of the instrumentals of one song with the vocals of another. And the more odd the pairing, the better.
The music industry has greeted them with mixed response. A radio station in London playing a popular mash-up with Christina Aguilera belting her hit Genie in a Bottle over the retro-rock of the Strokes was served with a cease-and-desist order by Aguilera's publisher, Warner/Chappell.
The rare legal mash-up
On the other hand, in Britain recently, Island Records released a legal mash-up, which entered the pop charts at No. 1. It combines music from three artists -- the new-wave icon Gary Newman, the R&B singer Adina Howard and the girl-pop group the Sugababes.
The music -- there are hundreds of such recordings -- is particularly popular in Europe. But through the Internet it is spreading to the United States. There are so many bootlegs using Eminem and Missy Elliott songs that some practitioners refer to making a bootleg as "doing a Missy" on a song.
When revolutions collide
The growing scene is a result of two colliding technological forces that have been revolutionizing music-making and the record business: cheap computer software, which makes it possible for a teenager with no musical knowledge to create professional sounding productions at home, and Internet file-sharing services, which provide a quick way to gather and share music.
Naturally, the music industry is concerned about this, because in most cases the tracks are being used without artists' permission.
But today, when the Internet seems to loom larger in many music fans' heads than lawyers' threats, bedroom musicians on both sides of the Atlantic are undeterred.
All they need to do is download or buy software programs like Acid (which automatically synchronizes the rhythms of different tracks). Then they can scour a file-sharing service for a cappella versions of songs. Then, using a program like Acid, they can combine the material into a new song.
Signs of a good bootleg
The mark of a good bootleg, fans say, is that it doesn't sound like one song superimposed on top of another, but a new song in itself. Among the most popular bootleg artists are Freelance Hell-Raiser (responsible for the Aguilera mix), Osymyso (who combines more than 100 songs in one mash-up), Kurtis Rush and Richard X.
"If you take two or three or four great records and mix them together, you should end up with a superior product," said Steve Mannion, a co-editor at Boom Selection (www.base58.com), a Web site dedicated to documenting the do-it-yourself remix, bootleg and sampling movements.
"The best bootlegs don't sound like bootlegs; they work at a profound level, and actually sound like they are the original record."
Bootlegging the bootleggers
Completing the circle back to the record store, an illegal CD collecting the year's best mash-ups, The Best Bootlegs in the World Ever, recently appeared on the shelves of independent record stores.
It was created by profiteers who simply downloaded the songs from a file-sharing service and then transferred them onto a CD.
"It is a case of bootleggers bootlegging bootlegs," said David Dewaele, who with his brother Stephen makes up one of the most accomplished and long-standing teams, known alternately as 2 Many DJs and the Flying Dewaele Brothers.
Last year, the Dewaele brothers, Belgians who also play in the popular rock band Soulwax, created a legal mix album, but not without a lot of difficulty.
It took the brothers two weeks to make the album, released as 2 Many DJs: As Heard on Radio Soulwax Pt. 2, (there is no Part 1) but nine months to license the music (which includes songs by Dolly Parton, the Velvet Underground, Sly and the Family Stone and others).
Even then, they were able to clear the music on the CD for release only in Belgium, Luxembourg and the Netherlands.
Though the album is available in the United States as an import only, some music executives who have heard it cite it as not only the remix album of the year but the best album of any kind released so far this year.
"It's my favorite record of the year so far," said Steve Greenberg, a former Mercury Records executive who now runs the independent label S-Curve Records. "It looks at music in a fresh and original way, and breaks down walls in ways that are particularly exciting considering how categorized and fragmented music is at the moment."
Keep the pace, baby
One of the Dewaeles' first mash-ups was a combination of the rapper Skee-Lo's light-hearted I Wish, Survivor's anthem Eye of the Tiger and the Breeders' rock song Cannonball.
Soon, the brothers had their own radio show, Hang the DJ, on Studio Brussels.
From the opening track of their album, there is a distinct style and aesthetic at work. Often, the songs are heavily cut up by computer, so that an introduction can be shortened, a verse removed or a section repeated to maintain the set's fast pace.
"It has to be something that has some sort of edge to it, something weird that makes you go, 'What is this!' " said David Dewaele.
Cornerstone of hip-hop
Making new songs out of existing works, of course, is nothing new. There are precedents in everything from 20th century classical to cartoon music, and it is the cornerstone of hip-hop, be it early pioneers like Grandmaster Flash or later innovators like Dr. Dre.
In the 1980s and '90s, avant-garde sound artists like Plunderphonic, Negativland and the Tape-Beatles (as well as the pop pranksters the KLF) challenged copyright law with collages made of everything from found sounds to top 40 hits.
But many musical observers trace the official beginnings of the British bootleg scene to the Evolution Control Committee, which in 1993 mixed rappers Public Enemy with music by Herb Alpert.
Today, there is a glut of such artists, and Mannion said that his Web site, Boom Selection, may receive as many as dozen new ones a week. Does that make it a fad or a genre that is here to stay?
"I don't know what will happen next," Mannion said. "When people hear this stuff so much, they can get bored of it. But to me, I'll never get bored with this stuff, because that's like getting bored of music itself."
