I have a good deal of experience with analog to digital conversion and some experience with mastering off of tape. Cookie is absolutely right that down converting from 24/96 or DSD to 16/44.1 causes a large loss of quality (as also the original AD conversion).
Most mastering engineers I know do 90% of their processing on analog equipment, for both digital and analog sources. They consider the extra AD/DA conversions to be worth it to use good quality analog tools.
What I’m not sure of is whether upsampling 16/44.1 to DSD digitally is inferior to playing a 16/44.1 file through analog and converting with another AD converter to DSD. That is certainly the way to do it if you have good analog processors that you want to use, or need to add some flavor to the digital file.
Those losses in downconversion (e.g. 24/96 to CD format) make me wonder how some hear a superiority of disc drives … but probably just compared to the redbook files streamed, not the hires files. I guess generalization in many regards is not good most of the time.
Ted has stated elsewhere that it is possible to resample to any arbitrary Freq but the quality of the conversion process depends on th precision of the maths (if understand correctly). In the majority of implementation s an integer change (eg 48 to 96) the chances of getting a good job is much higher.
44.1 to 48 or 96 is not an integer conversion so I guess unless you have a theoretically perfect conversion algorithm you may be better using an interim analogue stage to avoid “bad math”.
To convert 96k to 44.1k you need to upsample by 147 (to 14.112MHz), do a great brickwall filter job with a cutoff a little lower than 22.05k and then downsample by 320 (and possibly dither to 16 bits). And yes you need to have reasonably good precision on your filter coefficients (say 30 bits) and use about 60 bit precision math. It used to be that a lot of such convertions used sloppy math and or sloppy filters, but now iZotope filters (just as an example) do well and are available in many players and editing systems.
