https://support.apple.com/en-us/HT212183#:~:text=Can%20I%20l....
We don’t cry over bitmaps vs vector graphics in most contexts, especially that the hardware is trivially limited. It’s probably a bit more nuanced with speakers, but I imagine that they also have very real limits on distinguishable outputs for a given input, even if it is not as trivial to see as in the case of a w*h pixel grid of depth n.
So yes, I think mp3/aac to CD, the change is very noticable. CD to HD (24bit), not so much
It might be possible that with very ($1000+) high end headphones about 5% of people could tell a difference, but even that is questionable. I have done many blind A/B tests with my $500+ headphone setup and no one has ever been able to accurately tell the difference repeatedly. There is absolutely no way that someone would be able to discern the sound difference between 320 and lossless on an AirPod-quality speaker.
I’m not sure about large speakers however. I assume that it’s equally difficult to tell any difference, and I couldn’t when I tested my setup. However, I have listened to some incredible $4000+ speakers before, and at that level I wouldn’t be surprised if differences emerged.
There’s so much snake oil in audio and placebo can effect sonic perception so heavily that it’s nearly impossible to find anything objective. There’s also a lot in the chain - the DAC, the AMP, room acoustics… that will effect the sound, sometimes substantially - let alone the speakers and the actual source.
While microphones obviously exist, you can’t measure sound the same way that you can measure the nits and white point of a monitor - it’s far more intangible.