In article , Arny Krueger
wrote:

"Jim Lesurf" wrote in message
...

It is an interesting question. However for myself, the main 'bar' to
giving any answer is the absence of detailed technical information on
HDCD that would let me determine what *actual* effect the process
has... I've read all sorts of claims and general descriptions over the
years that 'describe' HDCD, but none that would enable any analysis,
etc. (Indeed, the descriptions I've seen at different times
contradicted one another!)

I seem to recall that there was an AES conference paper that laid out
some of the details.

Thanks. I'll have a search for it when I get a chance. :-)

My recollection is that HDCD was based on an attenuator that was
switched on and off by proprietary data patterns that were encoded in
the LSB. If your player didn't have the HDCD feature then you got
little bursts of noise at the level of the LSB, which is generally
inaudible. If your player had the HDCD feature, then the trigger data
was muted and an attenuator that extended the dynamic range downward
was turned on or off as needed.

I've seen descriptions along those lines before, but none that gave any
detail... until Adrian's and your own postings later in this thread!

Given that no commercial recordings have more than about 75 dB dynamic
range, the added dynamic range extension beyond the standard CD formats
96 dB or so, is moot.

Indeed. Also, since we can expect well-recorded examples to have used some
form of noise shaping, the 'vanilla' CD spec may well provide a better
audible performance than is required even for signals with a wider range.

Slainte,

Jim

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