Super audio compact disc

Super audio CD (SACD) is a derivative of the compact disc developed by Sony and Philips, with a larger storage capacity that is used to record music at a higher bit-rate.

Although the same physical size as the compact disc SACD uses a different kind of digital audio signal, Direct Stream Digital (DSD). DSD is 1-bit and has a sampling rate of 2,822,400 Hertz. This gives the format a greater dynamic range and wider frequency response than the CD.

Hybrid SACDs are a dual layer SACD with a CD layer [16 bits/44.1kHz] compatible with traditional CD players. using a process called Super Bit Mapping Direct, the hybrid disc's CD layer can approach 20-to-24-bit precision [1].

A CD uses PCM digital audio and is 16-bit with a sample rate of 44,100 Hertz.

Currently, there appears to be a high resolution format war between Super Audio CD and DVD-Audio.