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.
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.
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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