This might be the wrong place to ask but whats HDCD? How can I play it on my mac and take advantage of it? Also what hardware would I need to play on my sound system?
You can play HDCDs with Windows Media Player 9 or above on Windows XP only, which to this date is the only software-based decoder available. Microsoft bought the rights to it a long time ago.
If I remember correctly, HDCDs play like regular CDs in hardware without the decoder, but in the presence of a HDCD decoder, adds a few "features" to regular Red Book standards.
To be honest, not many have either the setup and/or the ability to hear an obvious difference in HDCD vs. regular CD audio. But whatever floats your boat.