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Gene Genie

The next version of hpDJ, HP Labs' experimental dance-mix system, will be able to create new music by 'breeding' new tracks from successful sound genes

May 2002

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Last year HP Labs researcher Dave Cliff invented a digital DJ that could mix dance tracks as well as a talented human. Now Cliff, working with fellow HP Labs researcher Guillaume Belrose, has taken his invention to another level.

hpDJ can sense if dancers are enjoying the show and, if not, change tracks or even create its own n ew music using genetic algorithms

He has devised a new version of the hpDJ system that can sense if the dancers are enjoying the show and, if not, change the tracks or even create its own new music using genetic algorithms.

how it works

Here's how it might work. The club has been jumping all night to hpDJ's high-energy dance mix. But when a new track starts, the mood changes, and people begin drifting away from the dance floor.

record player

No problem: hpDJ can recapture the mood. At this club, the dancers wear biofeedback devices on their wrists or as earrings -- more like fashion accessories than high-tech devices -- designed to monitor the wearer's motion, location, temperature and heart rate.

This information is fed to hpDJ over a Bluetooth-style wireless link, allowing it to tell how many people are on the dance floor and, from their temperature and heart rate, how much they are jumping around.

keeping them dancing

If enough people move away from the dance floor, their heart rates drop and their physical locations change -- telling hpDJ the present track isn't going down a storm. hpDJ's immediate response is to play music that will get people dancing again. It could add another track from a top performer to the mix.

Or, using genetic algorithms, it could 'breed' new tracks, rapidly experimenting with unique rhythms until it gets positive feedback from the floor.

HP has recently applied for a new series of patents for ideas invented by Cliff, himself an enthusiastic amateur DJ, which makes possible this vision of an automated dance system.

new version

Why the new version? When a fragment of a mix from the original hpDJ was played to BBC radio DJ Judge Jules last year, he commented that the system would never be better than "the human real deal" because it couldn't respond spontaneously to the dance crowd's mood.

"It was a valid point, so I started to think about how I could make hpDJ react to the crowd," said Cliff, an artificial intelligence expert and former professor at MIT.

But even human DJs aren't perfect, says Cliff. "I've been dancing in a club and the DJ doesn't pick up on the mood of the crowd, playing music that's not really what they want. On the dance floor you can feel it: people lose enthusiasm, and it can be a big disappointment. The new hpDJ will let people avoid those situations."

next steps

His colleague, Guillaume Belrose, has developed the genetic algorithms that the system will use to auto-compose dance music. Belrose, a keen amateur musician, is using drum rhythms that go on to generate new sounds.

"The next step is to create more complex music-based on audio samples," Belrose said. "The aim of the future hpDJ genetic algorithm is to create, in effect, DNA for sample-based dance music tracks, let them evolve and see which survive -- which ones people continue to dance to."

still to come

Demonstrations of the technology may be made available over the Web this year. As for the hardware -- the biofeedback devices, for instance -- this is further down the line.

An interim solution could be to let people vote for tracks using push buttons. Another of Cliff's patent applications uses sophisticated software to track people's activity through a pressure-sensitive dance floor and infrared video cameras, so no one needs to wear monitoring devices.

by Julian Richards


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Researchers Guillaume Belrose and Dave Cliff at the mixing board.
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