HDCD is a format that "magically" encodes 20bits of data into 16bits. There is a signal bit in the stream that identifies it as HDCD. If the decoder takes the HDCD data and converts it to 24/96 the player has no way of knowing that the original source was HDCD. If you configure Foobar to pass HDCD PCM unmolested to the player then the light should come on. Although depending a how/where the HDCD decoding is done in the player that light still may not come on when not using the physical disc. HDCD 16bit PCM can be played just fine without decoding, just slightly lower SNR.
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Larry_s, AFAIK HDCD coding is a combination of peak extend (improved dynamics) and better filtering with interpolation. Redbook CD has limited dynamic range (otherwise everybody with a boombox or small system would complain about buzzing speakers or neighbors that go crazy), but HDCD compression can be reduced since person buying it most likely has decent system. So, it is possible that dynamics with peak extend are higher but without resemble normal. I also suspect that most of music released (at least initially) on HDCD sounded good to start with (marketing). One of the reason for newer formats (HDCD, SACD) is better copy protection since they loose a lot of money on piracy (SACD cannot be copied at all because of pit width modulation). Could protection be the reason for Cary decoding only from CD?
Thanks for all the feedback and info.
With an HDCD it does trigger the light and recognisesthe content. On some Cds it sound better other upsampling is better. Better meaning more dynamic and detailed. There is no way to turn it off and on. Just use the upscale and the HDCD light goes off.
I renmoved the HDCD plug in from foobar and that wasnt succesful. Also tried with Real Tek Audio manager at 16/44 and 24/96 and no success. Unofrtunatly I havent found a way to let the reak tek manager use the sources sample rate and bit depth. Maybe the issue is that is filtering out the 'magic'.
It does sound great and works well having the spdif input. I use a switch box that has HDMI/SPDIF for the inputs. So the Sat/Bluray/HDdvd signal travels to through the to Cary. Sounds much better than the analog outputs.
Ill look around and see how to send the PCN signal unmolested from foobar and if that does it. Anyone awrae of a diffrent audio manager to replace the realtek one?
I'm definitely not as knowledgeable as the other posters, but I'm thinking that once HDCD encoding is taken care of by foobar, then the DAC should not "know about it" and the HDCD light not coming up is correct.
The Cary is now fed a 20 bit word PCM stream, "synthesized" by foobar from a 16 bit, HDCD-encoded stream, from which the HDCD "marker" has been removed.
Here is some more explanation of the HDCD encoders in foobar (and other software implementatons) and why it is not as good as the original hardware implementation. The 16 to 20 bit extensions are done, but the digital filters are not implemented in the software versions. The Cary 303/200 has the original Pacific Microsonics chip, so should be better than the software implementations.
From the person who wrote the HDCD decoder in foobar "only gain and peak extension are applied. Transient filter is not supported, as there is no reference software to base the filter on. Besides which, the transient filter is really only useful if you're also upsampling the output to 88200Hz, or at least so I've heard." Quote from hyrogenaudio thread, post 97 of this thread
foobar HDCD discussion on hydrogenaudio
From Goodwins High End website
"Every CD player has a digital filter that is an integral part of its sound reproduction electronics. In addition to decoding HDCD recordings, the HDCD decoder chip used in consumer products also contains the HDCD high-precision digital filter that improves the sound quality of all types of digital audio recordings."
David256 - read my comments above. dBpoweramp uses the same code as foobar. It does part of the job of the old Pacific Microsonics chip, but not all of it. A DAC with the old chip will do a better job of reproducing the original HCDC sound than the software solutions.
Helian's point is important and needs to be checked out.
I have ripped all of my CDs in FLAC or APE. All of my HDCD's play on my 306/200 and 302/200 with the HDCD light on through coax, toslink or AES. Windows tends to mess up the outgoing bit stream. Use ASIO or Direct Sound in your sound card. Get a good sound card - it make a difference. I have found several USB sound cards that upscale to 48 kHz and will not work. You can hear it!
The older Cary players are very susceptible to jitter. I use an RME sound card with great results. I notice a huge improvement over my old M-Audio 2492 card.