Would those be HDCD cd's?

No, HDCDs are not 24/96's.

HDCDs are simple linear PCM 16/44.1 discs that have been encoded differently some how... (Filtering, DPS'ed, sound shaped; help... )

I thought HDCD was 20/44.1 ... that it's "claim to fame" was that extra four bits per sample which gave increased dynamic range.

------------------
Matthew J. Hill
matt@idsi.net

Matthew- HDCDs may claim to have 20 bit *resolution*, somehow due to how the signal is encoded (...), but the CD linear PCM red book is strictly 16/44.1.

Maybe I'm confused, but I thought HDCDs were not red book.

------------------
Matthew J. Hill
matt@idsi.net

They have to be red book, otherwise how could a normal (non-HDCD) player play them?

I keep hoping someone will get motivated and look up HDCD on Google or something and fill in the blanks here...

HDCDs are still red book audio CDs. They hide codes in lower order bits. On a regular CD player, this isn't audible -- way below normal sound levels. An HDCD equiped decoder recognizes these flags, and uses them to actively alter the playback sound. This includes dynamic range expansion, and some filtering/dithering effects.

HDCDs developer's claim this offers _equivalent_ quality to higher bit rates, and higher bit depths.

Of course, they also claim that it improves playback quality on non-HDCD devices, too.

Does it really sound better?? Like most audio things, there is no clear answer. I have a HDCD player. Although I _think_ I can tell a difference, I probably couldn't in a blind test.

big mac- Thanks!

Sony also has this thing (in the DAT world) called Super Bit Mapping. Also utilizes simple linear PCM 16/44.1. But what it does, is to move the "noise" from the audio spectrum where humans hearing is more sensitive, to a part of the spectrum where it's less sensitive.

Sort of like a filter , but not really.

The wierd thing? Test measurements say that with SBM, it's worse, but when people listen, it's better. The claim is 20 bit resolution in terms of *apparent* signal to noise ratio.

I thought HDCD's did require a special player or an external decoder fed via the digital out? I do know that XRCD's do not require any special player or decoder and they meet the redbook standard but still mananage to fit more than "normal" data on the discs. I haven't found an XRCD that I already have on standard redbook or SACD, so I can't compare, but the one I picked up to check out the format sounds very good (Count Basie - Basie's Big Band)

------------------
pat----

email: pat@sklenar.info ---===--- home page: Grumpy's Lair

HDCDs will play in any standard player.

I often wonder if the sound quality from these special formats is really due to the formats, or just special care taken during mastering/remastering.

I have a CD from Audiophile, has a piano recording done simultaneously through multiple formats. Analog, various tape speeds, different digital formats, some active filtering/shaping, and HDCD. The change among the various analog, and from analog to digital is pretty easy to pick out. I'd have a hard time being honest about being able to tell the difference between straight 16 bit/44 CD and HDCD.

So, if a disc has been remastered as part of going to HDCD, I would be suspect about any quality differences really resulting from HDCD itself.