I’ve always kinda wondered about this. I’m not an audio guy and really can’t tell the difference between most of the standards. That said, I definitely remember tons and tons ‘experts’ telling me that no one can tell the difference between 720p and 1080p TV at typical distance to your couch. And I absolutely could and many of the people I know could. I can also tell the difference between 1080 and 4k, at the same distances.
So I’m curious if there’s just a natural variance in an individual’s ability to hear and audiophiles just have a better than average range that does exceed CD quality?
Similar to this, I can tell the difference between 30fps and 60fps, but not 60 to 120, yet some people swear they can. Which I believe, I just know that I can’t. Seems like these guidelines are probably more averages, rather than hard biological limits.