HDCD FLAC FOOBAR SPDIF Cary 303/200 HDCD

The plug-in only partially reproduces the full HDCD decode. If the Cary does the whole process you may be better off turning off the foobar decoding. As Larry says, that should let the original signal pass to the Cary and the Cary can do the proper decode.

Without decoding dynamics might be lower and data will be only 15 bit since bit #16 is used to switch dynamic range.

Kijanki, I believe what you said is true only if encoding is done with HDCD Peak Extend. Don't know if that's always done or not. The 16th signal bit and decoding hints is usually in only 1-2 percent of the data samples.

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?

How does it sound?

That really is the only part that should be a concern. If you have the physical media it will not matter anyway. Put it in the player and enjoy!