HDCD VS SACD

The difference is that one is an enhancement to an existing format while the other is an entirely different format that is not compatible with the other. HDCD is a process that is added to Redbook(regular CD's) developed by Pacific Microsonics. It is a playback only decode system, which means that it's benefits are applied during the playback of standard Redbook CD's and is only compatible with that format. SACD is an entirely different format that is not HDCD compatible. SACD uses a much higher sampling and bit rate digital encoding system known as DSD or Direct Stream Digital. A disc that has a DSD layer will require a playback device that is compatible with that format. The good news is that most SACDs also include a standard Redbook layer that can be played back on conventional CD players. Thopse discs DSD layer however can not be played back on a conventional CD player. Hopefully this clears things up

I realized that I really didn't answer your question. While the majority of people agree that HDCD is an improvement over non HDCD CD's it is not the equivalent, sound quality wise,to SACD's which use a much higher sampling and bit rate than conventional CD's and therefore offers higher fidelity. Well that's the way it's supposed to be anyway. For now some of the very best Redbook players can offer performance that is virtually indistinguishable from even the best SACD players. This is a result of disc player manufacturers having not yet perfecting playback hardware for SACD. Considering that it is for all intents and purposes a dead format that maturation for SACD hardware is unlikely to ever occur. Normally and with some exceptions even lower cost SACD players will be able to produce better sound with DSD encoded material than all but the very best Redbook CD only players, playing back CD's.

One additional point. Even though SACD is fading, there are many more recordings available now and still being released than there were on HDCD.

Kal

I have several HDCDs, they play on my system that usually includes a DAC produced before HDCD was introduced, do they add anything in this case or just play as standard discs? The format came up during my sabbatical from audio and I have never been clear on exactly how it operates.

I can't comment on SACD, but I do own a Rotel CD player with HDCD capability and several HDCD encoded CD's. Let me be blunt, whenever I seriously look for CD's to purchase, HDCD encoding is the closer for me. If you like vinyl, you'll love HDCD discs.