Greetings Google Researchers.    I could have figured this out myself
by using a big magnet but decided not to waste a CD and ask you.   Are
recorded CDs subject to magnetic interference?   For example, if I
mail someone a CD with recorded music on it, will it be degraded or
made unusable by coming in contact with some magnetic field during the
process of being delivered?

Greetings seattle-ga!

No, regular CDs are not subject to magnetic interference.  Since no
magnetics are involved in the process of creating a CD, the CD will
not be degraded by coming into contact with some magnetic field.  It
is an opitcal media, not a magnetic media.

"compact disc destroyed by magnetic fields?" newsgroup thread:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&th=c27dfaf2c65c0183&rnum=1

In another newsgroup thread, an employee of the CD-Info Company wrote:
"Compact disc is impervious to magnetic fields,  moisture (within
bounds -- I know a guy who put a CD-R in the Pacific Ocean at 100 feet
for 6 months, retrieved it and it still worked, but it's possible that
years of high humidity and high temperatures might have a negative
effect), and shock."
above text from "Magnetic fields and CD-Rs":
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&th=b226b453e56b960b&rnum=3

Back in 1990, Nimbus Records of England did some research on CDs and
determined that the breaking down of some of the chemical used in CDs
would eventually effect the quality of the CDs.  I believe CD
manufactures have changed some of their processes since then.  They
also research cassette tapes and found that "the tapes shrugged off
excess heat, shaking, dropping and even stray magnetic fields."  The
article makes no reference to magnetic fields affecting CDs.
"Research shows vulnerability of CDs":
http://aroundcny.com/technofile/texts/cddestruct90.html
"A time bomb in your compact disc?":
http://aroundcny.com/technofile/texts/cdcorrode91.html

However, there are magneto-optical disks used to store computer
data.  They do not play on regular CD players.  These types of disks
*would* be affected by magnetic fields.  According to the following
page, "the convention is that when referring to magnetic media, it is
spelled disk.  Optical media like CDs, LaserDisc, and all the other
formats are spelled disc":
http://www.siggraph.org/education/materials/HyperGraph/video/mpeg/mpegfaq/mpeggloss-c.html

You might see MO disks used for things such as databases in libraries.
 A little more info on the MO media:
"What is a Magneto Optical (MO) drive and how does it work?"
http://sony.storagesupport.com/cgi-bin/sonysupport.cgi/vMWTNEmrLd-RAENOx0NmPXnz8R14UCwo/faq/view/443

Some other CD-related reading:
"CD or not CD, a burning question":
http://www.oncomp.com/feb01-3.htm

I hope this information is helpful.  If you would like for me to
clarify any part of my answer or further research your question,
please let me know before issuing a rating.  Thanks!


leep-ga


some search strategies:
"compact disc" + "magnetic fields"

Thank you!