Digital eXtreme Definition.


DXD is plain PCM with 24 bit / 352.8 kHz.

As DSD (single bit) is not suit for editing, DXD was developed for the Merging Pyramix workstation and introduced together with their Sphynx 2, AD/DA converter in 2004. This combination meant that it was possible to record and edit directly in DXD.

The final product is converted to DSD and publishing on SACD. 


Source: Wikipedia