big mac- Thanks!

Sony also has this thing (in the DAT world) called Super Bit Mapping. Also utilizes simple linear PCM 16/44.1. But what it does, is to move the "noise" from the audio spectrum where humans hearing is more sensitive, to a part of the spectrum where it's less sensitive.

Sort of like a filter , but not really.

The wierd thing? Test measurements say that with SBM, it's worse, but when people listen, it's better. The claim is 20 bit resolution in terms of *apparent* signal to noise ratio.