24/192 Big Improvement Over 24/96????

I agree the recording/mastering is the biggest factor. That said, I think what Chord Electronics has to say about hires is interesting .. 1st four paragraphs in particular:

http://www.chordelectronics.co.uk/chord-dac-technology.asp

Bifwynne, and the paper at the xiph link he gives, is precisely correct. Formats for playback at a bit depth & sample rate higher than 16/44.1 do not and can not sound *intrinsicly* one bit (pun intended) better to human hearing. In fact, they may in some real world circumstances actually sound worse. Studios, including myself, often do their work using higher bit depths & sample rates for very valid technical reasons. The critical difference to the final listening experience is in the mixing, mastering and the final conversion to 16/44.1. (NOTE: typically different masters are produced for different formats, including, most especially, LP.) IF studio production is done properly (too often it isn't, IMHO), and IF the playback kit is of even moderately good quality, 16/44.1 has the potential to give the final listener as good sound quality as can be had. Any higher rate format should at the very least be a waste of media space and money. If you think you hear a difference, and you may, be assured that the difference is NOT due to the format itself.

The xiph.org article concentrates only on whether a given signal can be described sufficiently by 16/44.1. Several subtle and crucial differences between storage and playback of such a file have been pointed out in a white paper by Marco at HiFace and elsewhere.

The discrepancy between viewpoints is at least partly due to the variable behaviour of 16/44.1, 24/96, 24/192 and DSD files in each DAC. The bottom line is that is depends largely on which converter you're using and how it handles not only higher bit rates, but also bit rates based on 44.1MHz and 48MHz families (ie 24/88.2 vs 24/96).

So, yes, you could argue the difference is due to the format itself, but it would be truer to say that the real issue is how each converter handles the format, and less about how 'much information' it contains.