🚀 go-pugleaf

      I sense a little confusion here. Oversampling and noise-shaping are irrelevant
      to each other. Ovesampling is
      an economical means for exploiting the ability of digital
      filters to obtain desirable frequency and time-domain
      perforamnce. Noise shaping relates to amplitude domain
      performance. It is a means for forcing quantization error
      into frequency ranges where the ear is far less sensitive.





In requantising, noise shaping is a purely digital process - it only has an analogue component when it's used within a quantising process. In an oversampled DAC, this is entirely digital, with no more than a single order RC filter to keep the RF out of the following stages. I suggest that you go and read John Watkinson's 'Introduction to Digital Audio' carefully.

      It turns out that brickwall filtering at 22 KHz or so has never had to
      be the sonic disaster universally ascribed to
      it by some. If people listened with their ears as opposed to
      their eyes...





It's not a disaster, but the effects are clearly audible under some circumstances. Not only that, but it's well documented in peer-reviewed literature going back decades - check out the Journal of the AES, issue 32. It's also not the only reason for complaints - there are enough poor-sounding converters around anyway with all sorts of other deficiencies which stand out very clearly in any sort of listening test you choose to do. We are not talking 'golden eared' here either...

      So why do we tolerate and ignore sharp roll-offs, massive phase shifts
      and immense group delays in
      the bass range while obsessing over often smaller
      (numerically speaking) similar effects in ranges that many
      think is above audibilty?





Partly because of the way our ears use phase as a part of timbre detection, and the fact that the ear's critical bands are consequently rather narrower at low frequencies. It rather depends on what you are used to hearing, as well - once you have learned to recognise bass phase shifts (which is harder to do, for the foregoing reasons), then you would possibly dislike them just as much - but the human ear is rather more tolerant of absolute phase differences at low frequencies, and this has never been percieved as anything like as much of an issue. Also, the vast majority of listeners don't have systems that can accurately reproduce low frequencies anyway, and they are used to the way they sound - however flawed this may be. And I don't think that many people are that attuned either to what bass is really supposed to sound like - they don't actually get exposed to very much real bass music, after all. It all makes a difference...