CLUBBERS will soon only have themselves to blame if they don’t like the music
they’re dancing to. Artificial intelligence experts at Hewlett-Packard have
developed a computerised DJ that uses feedback from the dancers to generate new
music.
Dave Cliff of HP’s laboratories in Bristol says that the “HPDJ” will monitor
the way dancers respond to the music and compose new tracks according to how
animated the crowd becomes.
Last year, 91av reported on an earlier version of the HPDJ
and pitted it against a human DJ in a London venue to see how it fared with a
live audience (23/30 December 2000, p 56). Although the software managed to fool
a third of the clubbers into believing a human DJ was at the turntables, our
panel of professional DJs was more sceptical. But then again, they’ll be the
ones to lose out if it works.
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The earlier version takes dance tracks and works out the best sequence in
which to play them. It can also mix them—seamlessly fading one song into
the next while adjusting the tempo.
Cliff says that the biggest gripe that DJs such as BBC Radio 1’s Judge Jules
had with it was that it couldn’t gauge the crowd’s response to the music. That
got Cliff thinking about ways to improve it. His solution is to give each
clubber a device like a wristwatch that monitors their behaviour, feeding info
back to the HPDJ via a “Bluetooth” wireless link. “It tracks your location,
measures your heart and perspiration rate, and an accelerometer monitors how
active you are,” Cliff explains.
Every dance song comprises a number of different tracks, such as drum
patterns, bass lines, keyboard hooks and vocals. To create a song, the HPDJ
chooses tracks from a large library and then modifies and overlays them, based
on the vibe coming from the dance floor.
So how does it work? The HPDJ uses a “genetic algorithm”, a type of program
inspired by evolution. It uses a survival-of-the-fittest approach to create new
and better tunes. In the case of the HPDJ, the different tracks are the “genes”,
and the inputs from the dancers are the “fitness” factors, essentially deciding
whether or not particular combinations of genes survive.
If the track sounds so awful that people can’t get into it, they may wander
off to the bar or dance less enthusiastically, says Cliff. So HPDJ will then try
to improve the music, experimenting with different beats and bass lines, or
speeding up the tempo in a bid to coax more people back onto the dance
floor.
When the crowd gets into the music, the HPDJ will sense that more people are
on the dance floor and monitor how actively they’re dancing. It will then
gradually build up the tempo to whip the dancers into a brief frenzy, before
calming things down for a chill-out period. Cliff also envisages a novel
spin-off: the software could be linked to a CD recorder, so as you left a club
you’d be given a CD with the music you helped to create.