"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.

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.

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.