> Generally means they got the dithering wrong. (You might be hearing the dithering actually.)
Who are "they?" And when was I converting higher bit rates to lower? I have no issue distinguishing between pro-quality 16-bit and 24-bit ADC, no dither involved. This is not exceptional, and many can consistently distinguish between them even not knowing before hand which converter was used. It is theorized that ultrasonics picked up by the higher converter can affect sounds at a lower frequency, which can be heard. 32-bit ADC sounds no different to me than 24-bit, and though I understand the application, I've never needed absurd amounts of dynamic range.
> The problem is that it always sounds like it's coming from the same direction
Once a proper stereo field is created, a listener can not accurately tell from where sound is coming, regardless of head movement. That they falsely believe they can is only due to psychoacoustics: they see a speaker and assume it is the source of the sound. Repeated studies involving arrays of speakers with only two active have confounded listeners who have insisted sound was coming from inactive speakers above and behind them.[1] These studies were performed in a large room with wall treatment, and the listeners were allowed to move around the room (and obviously were not paralyzed to prevent them from turning their heads). Because you know where the speakers are, you will assume sound is coming from them. A stereo field will not collapse if you turn your head, unless the stereo field is only as large as your head or smaller. Your assertion is false.
> But it doesn't matter how many ears you have.
This is ridiculous. If you only had one ear, or were deaf in one ear, you could only hear in mono. This is known as counter-example proving your assertion incorrect on its face.
> The problem is that it always sounds like it's coming from the same direction, because it's premixed. Can't turn yourself around and have the front and back switch, or move your head around to get a better localization.
Again, the reason why you confidently believe you know where reproduced sound is coming from is because you can see your speakers, you know where they are, and obviously, that is where you know sound is being produced. Sound localization is confounded by sounds bouncing off surfaces and reaching one ear or the other, in one example, before those coming directly from speakers. It is impossible to determine if the sound was directly perceived or indirectly perceived, namely because sound is invisible.
If you have a tiny stereo field, what you describe is possible. This is common in DAW workstations set up to maximize space, and this is why professional control rooms are larger and have more than one set of speakers placed at different distances apart from each other and further away from the engineer. IOW, it is the reason medium and far field monitors are necessary to properly mix professionally. Once one or both ears are outside the stereo field, you'll have a different aural effect. But if your stereo field is large enough (which necessarily involves increased sound pressure) and your ears stay within it, turning your head, standing upside down on your head, or turning around will make no difference.[2] Your ability to determine the sound direction is only reinforced by what you see and what you know. If you were blindfolded and did not already know where your speakers were, in a properly treated room and listening within a stereo field, you would not consistently be able to determine where your speakers were nor if you were listening to stereo or surround sound. These beliefs that one can determine sound direction in only a stereo field are engrained due to assumptions and visual cues, and due to the home stereo industry that marketed surround sound for the home. The only way to dislodge these false beliefs is in a full demonstration set up like the studies I have described above. Only when you are certain sound is coming from one speaker and not another, and shown that the speaker you insist is the source of the sound you hear is not connected to anything and not active will it finally click, and you'll recognize the power of psychoacoustics and how you've been fooling yourself all along.
[-1] https://en.wikipedia.org/wiki/Auditory_illusion
[0] https://en.wikipedia.org/wiki/Franssen_effect
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744263/
[2] https://en.wikipedia.org/wiki/Sound_localization#The_cone_of...