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HDCD Decoding ?

Recently, I have noticed that the specifications for CD players sometimes mention that they are compatible with HDCD CDs. I thought that HDCD died about ten years ago. But HDCD CDs have always been playable on any CD players; albeit not all CD players would decode the HDCD formatting because that required a special digital filter from Pacific Microsonics.

Several years ago, when HDCD first appeared, Pacific Microsonics required that anyone licensed to use their HDCD filter had to install automatic attenuation in their players for ALL non-HDCD discs. This was not necessarily a good thing.

When a 21st century CD player will read HDCD discs, it may or may not perform the automatic change in volume as a result. The net impact in older HDCD players was that all normal (non-HDCD) discs were attenuated. I own a few hundred CDs and only about 6 of them are HDCD. I expect that now in the year 2013, this is no longer a problem regarding the Pacific Microsonics HDCD filter. My guess is that current players are not using a Pacific Microsonics filter.

Perhaps "compatible with" is simply a reminder that the CD player will play the older HDCDs as regular CDs?

What says the group mind?
poetcatullus
kijanki's avatar
kijanki
4,432 posts
 
HDCD is recorded with least significant bit switching dynamics of remaining 15 bits. Standard CDP will read only 15 bits with noise on bit 16 plus weird dynamics - am I missing something?
hifiharv
351 posts
 
Your post raises some interesting concerns. I never knew about the attenuation. Always wanted a HDCD player for those Live Dead discs. Hope someone with tech knowledge will chime in on the facts here.
isochronism
2,893 posts
 
Live Dead is an oxymoron. I had to ad that observation and realize that is of no help.
Post removed 
poetcatullus OP
53 posts
 
This issue about which I raise concerns was well-known at the time and mentioned in Stereophile every time they reviewed a piece of equipment with HDCD capability. They generally made a point of praising the manufacturers who chose to implement the attenuation (required by the Pacific Microsonics HDCD license agreement) in the ANALOG domain rather than in the DIGITAL domain by simply cutting off a bit (thereby "punishing" all the normal CDs in ones collection for the benefit of the HDCDs).

There were certain pieces of gear where one could contact the manufacturer directly after purchase and they would accommodate the purchaser by telling them how to open up the unit and move a jumper, thereby undoing the compromise to their regular CD collection by reversing the attenuation and having all CDs play at their natural volume levels.
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