Super Audio Compact Disc. Philips/Sony’s proposal for a next-generation CD which combines DVD technology to produce a hybrid disc that will play in conventional CD players, but offering better audio quality than currently available CDs when played in a DVD player. The upper later is the “conventional (Red Book) layer, while the lower layer provides around 4.7 Gb of high-density storage, increasing the audio capacity to 4.7Gb, the same as a first-generation DVD, and allow text, graphics, and video alongside audio. Audio will be encoded via either standard 16-bit PCM at 44.1kHz, or “Super Audio” using Sony’s DSD data format and Philips’ DST data compression technologies, yielding 74 minutes of six-channel audio with purportedly a frequency response of DC–1MHz and the same dynamic range as conventional digital recordings of 24–bit/96kHz resolution. SACD employs SBM noise-shaping, and PSP copy protection. The intention of the SACD standard is to ultimately combine a stereo DSD track and a six-channel DSD surround mix, plus optional data, text, graphics, and video data. Here is a comparison between conventional (Red Book) CD and (the current (3/99) prototype specification for) SACD:
