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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
nsgarch's avatar
nsgarch
2,524 posts
 
Sonic, I know this isn't scientific, but what percentage of disks that indicate HDCD when played, would you say are unmarked 'HDCD' on the disk itself, or the case?

It's interesting to speculate why a performer would keep it a secret (especially Neil Young!) unless MS wanted an exorbitant fee to use the logo, and the performer figured 'screw you', my fans will find out on their own ;~)
aplhifi
515 posts
 
HDCD was developed by PM. The initial PMD100 decoder/digital filter chip was certainly one of the best at that time. PMD200 was the successor and based on Motorola 24bit DSP, so it was superior to anything else available. Then when more and more audio manufacturers started using powerful 24 and 32 bit DSPs from Motorola, Analog Devices, TI, Cirrus Logic, etc. to use in their products, the HDCD algorithm was something already available as a programming software to existing DSPs used for audio, so if a certain manufacturers like to offer such feature, they simply pay the licensing fees.
Bottom line, if you see "HDCD" light on a recent digital player, it means that it has a powerful DSP inside that takes care of it, usually in 32 bit precision. So it is the best HDCD processing you can get.

Hope this helps!
Alex Peychev
dtc's avatar
dtc
1,047 posts
 
There is some good information on HDCD on Goodwin's website, including links to original papers on the subject.

Information on HDCD

There is a also a very comprehensive list of HDCD CDs there.

HDCD CDs

According to the FAQ on that site the reason some HDCDs do not have the HDCD label on the case was that the artwork was completely prior to the mastering process.
poetcatullus OP
53 posts
 

Good news!

I emailed Oppo directly and sent them the link to this thread. Here is their response (which was virtually instantaneous):

"There is no attenuation for Red Book CD. When playing a HDCD the player will decode the HDCD from 16-bit to 20-bit then expand to 24-bit word length. CD and HDCD is still processed at 0dB reference, with extended HDCD done at -6dB to allow for the expanded dynamic range."

In a follow-up email they verified that the concern that started this thread is obsolete and that current HDCD capable players no longer attenuate standard CDs as they had done back when it all started almost 20 years ago.

I am grateful that we can now all move on and enjoy the music!
dtc's avatar
dtc
1,047 posts
 
Oppo customer service is truly outstanding.
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