[Reader-list] Copied Audio CD that can blow ure speakers

[Jaswinder Singh Kohli]

CD anti-piracy system can nuke hi-fi kit
By Tony Smith
Posted: 03/08/2001 at 10:27 GMT


Sony's Music Entertainment division has been testing an anti-piracy
technology that at best renders illegally copied CDs unlistenable and at
worse blows listeners' speakers.

The anti-piracy system, called Cactus Data Shield, was developed by
Israeli technology company Midbar Tech. Research conducted by New
Scientist magazine and reported in this week's issue shows how Cactus
works. Like Macrovision's SafeAudio, Cactus adds noise to the music data
stored on the CD. Unlike SafeAudio, Cactus flags the noise as control
information. On playback, this is ignored, but on duplication - even
with consumer CD-to-CD systems, which are not disabled by SafeAudio -
the noise disrupts the copier's error correction system.

The result: a CD-R full of noise, not music. Worse, the generated
waveform is of kind to which hi-fi and loudspeaker circuitry is
particularly sensitive. Play the noise-filled disc back at too high a
volume and - bang - your speakers are toast.

Frighteningly, the ability to damage equipment can be effectively
switched on or off by the CD mastering company by changing the
characteristics of the noise and thus the soundwave generated by
players' error correction systems.

Sony's Cactus tests, carried out, claims New Scientist, in Slovakia and
the Czech Republic were not set to nuke hi-fi equipment, but they easily
could have been it seems.

It will make an interesting test case when a punter sues Sony for
blowing up their loudspeakers after playing an allegedly pirate CD,
particularly if the music industry and consumer electronics companies
haven't issued warnings that pirate CDs can seriously damage your
equipment.

Midbar's technique, like Macrovision's SafeAudio, also plays fast and
loose with listeners' rights to make copies of discs for their own
personal use. Both companies claim the inserted noise does not affect
the listening experience.

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Regards
Jaswinder Singh Kohli
jskohli at fig.org
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