Super Audio CD (SACD) is a read-only optical audio disc format aimed at providing much higher fidelity digital audio reproduction than the compact disc. Introduced in 2000, it was developed by Sony and Philips Electronics, the same companies that created the CD. SACD is currently in a format war with DVD-Audio. Although neither side has made significant progress toward acquiring consumer acceptance, SACDs have an advantage over DVD-Audio in that most discs are hybrids compatible with existing CD players...

more »Media players that can play many formats (including DVD-Audio and SACD) are available for under $100.

SACD uses a very different technology from CD and DVD-Audio to encode its audio data, a 1-bit delta-sigma modulation process known as Direct Stream Digital at the very high sampling rate of 2.8224MHz ? with the typical sampling rate present on audio CDs currently being 44.1kHz at a resolution of 16 bit.

SACD authoring guidelines suggest that an SACD should always contain a 2-channel stereo mix[citation needed] though not all SACD have it (for example, in 2005 Sony Music Entertainment (Germany) GmbH released Charles Rosen?s performance of the Goldberg Variations as a hybrid SACD with 16-bit PCM and DSD 5.1 surround but no DSD stereo). They may optionally contain a surround mix ? either 5.0 or 5.1 layout. Although the disc always stores all channels, the surround mix does not have to use them all, and some may be mute; for example the 2001 SACD release of Mike Oldfield's Tubular Bells remains in the old quadraphonic 4.0 mix, and the RCA reissue of the 1957 Chicago Symphony Orchestra recording of Mussorgsky's Pictures at an Exhibition marks the first time the original 3.0 (three track) recording is available in a consumer format. The correct designation for the surround part of a SACD is "multi-channel", and usually has either the label "SACD Surround" or its own "Multi-Ch" logo on the back cover.

There are three types of SACDs:


* Hybrid: The most popular of the three types, hybrid discs include an audio CD "Red Book" layer compatible with Compact Disc players, dubbed the "CD layer," and a 4.7 GB SACD layer, dubbed the "HD layer."
* Single-layer: Physically a DVD-5 DVD, a single-layer SACD includes a 4.7 GB HD layer with no CD layer.
* Dual-layer: Physically a DVD-9 DVD, a dual-layer SACD includes two HD layers totalling 8.5 GB, with no CD layer. This type is rarely used. It enables nearly twice as much data to be stored, but eliminates CD player compatibility.

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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "SACD".