On 2/9/2012 4:28 AM, Mxsmanic wrote:
I've heard of bizarre copy-protection schemes that worked by removing part of
the sound spectrum from a recording, and I thought it might be something like
that, although I don't see how removing part of the sound would protect a
recording.
CopyCode was proposed, in about 1986, to be required by law
in the US as a means of identifying a copyright recording.
It worked by removing frequencies that presumably would be
masked anyway, and detecting the lack of those frequencies.
Congress tasked the (then named) National Bureau of
Standards to test the process to determine if it was
actually transparent to listeners. I participated in that
test myself. I could identify the difference with and
without CopyCode about 80% of the time, as could many others
in my test group (we were from the local AES chapter, not
that it means we were critical listeners). Congress
eventually nixed it, and it was abandoned.
You surely didn't hear a recording with this means of copy
protection. It just plain didn't work.
--
"Today's production equipment is IT based and cannot be
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it seems that it can be operated without a passing knowledge
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