An earlier generation of Naim CD players, such as the CDX2, used the Pacific Microsonics HDCD chip and could decode the additional information. The technology was developed in the mid-90s by Keith Johnson of Reference Recordings to bring the resolution to 20 bits by “hiding” additional information in the dithering. In an age of high-resolution files, this would appear to be an obsolete technology.
By the way, if you have a number of SACDs and want to get the DSD information, there is a way to do it if you have the right Blu-ray player. Do a search for ISO2DSD or SACD_extract to check this out or see the thread that I started elsewhere on the forum for more info about potential problems. Problems playing back long DSD rips with Naim app and NDS - #7 by JSchmidt