ezkcdude;130930 Wrote: > Of course, that would be stupid, because it wastes memory. However, > there are sound reasons to do this on the fly. Namely, upsampling > shifts aliasing artifacts (so-called ghost images) to a much higher > (inaudible) frequency range. As you alluded, upsampling does not add a > single bit of new data, but it can allow a designer to modify post-DAC > filtering (hopefully, for the better). As the terms are typically used, it's OVERSAMPLING rather than UPSAMPLING that shifts aliasing higher up the frequency range and makes life easier for the filters. Pretty much every DAC on the planet does oversampling these days (with the exception of the niche NOS ones, which some might consider to be out on the fringe). It's mathematically sound.
In contrast, upsampling (as the term is generally used) involves INVENTING additional data (usually by interpolation) in the expectation that it will deliver improved high frequency resolution. But this extra data that's invented can't ever be known to be correct. Quite a lot of the time, it'll be wrong. It doesn't "recreate" the high frequencies that were discarded when the recording was sampled at whatever lower frequency was used - that's impossible (as Sean pointed out earlier). In other words, the additional high frequencies generated are NOISE and/or DISTORTION. So how come people think upsampled digital audio sounds better? Maybe for the same reason that they think that analogue sounds better: that noise/distortion might actually be euphonic (if it's audible at all). -- cliveb Performers -> dozens of mixers and effects -> clipped/hypercompressed mastering -> you think a few extra ps of jitter matters? ------------------------------------------------------------------------ cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=26685 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
