Do you know precisely what HDCD actually does, as distinct from the remastering process?
HDCD is a registered trademark of Microsoft, they acquired the technology from a company called PMI in September of 2000. From their website:
"High Definition Compatible Digital. (HDCD.) is a patented encode/decode process for delivering the full richness and detail of the original microphone feed on Compact Discs and DVD-Audio.
"HDCD-encoded CDs sound better because they are encoded with 20 bits of real musical information, as compared with 16 bits for all other CDs. HDCD overcomes the limitation of the 16-bit CD format by using a sophisticated system to encode the additional 4 bits onto the CD while remaining completely compatible with the existing CD format. HDCD provides more dynamic range, a more focused 3-D soundstage, and extremely natural vocal and musical timbre. With HDCD, you get the body, depth, and emotion of the original performance not a flat, digital imitation."
"Audio chip manufacturers including Motorola, Sanyo, and Zoran have developed HDCD chips for audio products, such as CD and DVD players and receivers. HDCD-encoded media will play on machines that don't have the chip, and HDCD-equipped machines can play traditionally recorded media. Because the decoder chips include a high-precision digital filter, HDCD-equipped players will improve audio quality for even traditionally recorded CDs and DVDs. Conversely, because of the recording process, HDCD-encoded media will also sound better than traditionally CDs and DVDs on players that don't have the HDCD chip. Nevertheless, the best audio quality is yielded by HDCD-encoded media on an HDCD-equipped player.
