"Not just a CD, a better CD"
I came across a Sony Insert when SACD/DSD was introduced.
Direct Stream Digital (DSD): 1 bit, 2,822,400 samples per second. Dynamic range of CD 96db is extended to 120 db.
"Even the SACD’s 16 bit CD layer can sound better if it’s based on a Direct Stream Digital studio master. The Super Bit Mapping Direct process can be used to downconvert to the 16 bit CD format, which enables you to hear more of the original master."