A regular CD player will play the "red book" standard. This is 16 bit 44.1 KHz. It will also play HDCDs, but may not convert them as HDCD, just normal CDs. In this case you don't get the benefit of the HDCD encoding. XRCD is JVCs "Extended Resolution CD". It is playable on all CD players. It is "red book" standard, but the CD's are re-mastered and produced in a manner that gives much better sound--very high quality control on these CDs and in my experience all of them sound better than the original CDs. SACD is "Super Audio CD". It is a "DSD" encoded CD which means it is streaming digital, 1 bit at very high sample rates. There are two types of SACD. One is a hybrid which carries the "red book" standard on one layer and the SACD standard on the other layer. These hybrids can be played on regular CD players, but you don't get the benefit of the SACD encoding. For that you need an SACD player. The single layer SACDs are playable only in an SACD player, they will not play in a standard CD player. You can read more about SACDs on Sony's website. Hope that helps.
