i am puzzled by those who write off the benefits of high definition files and upsampling. Regarding the latter, consider a vinyl pressing. It is not possible to add more data to the grooves once it is pressed. However, one can extract more of the data in the grooves by improving the replay chain. A better RIAA device, superior cartridge, more rigid tonearm, better power supply, more highly engineered bearings etc. The same is true of redbook files. I find that a system that can perform a good upsampling of redbook files typically sounds "better" (to me at least) than one that does not. I find a similar improvement in files that have been recorded in hd. If others don't perceive the same improvements that is fine.