[scns]

A treated room would be the most impactful, DACs the least.

[yellowapple]

The DAC is pretty impactful if it's outright incapable of outputting anything beyond the usual 48kHz :)

[vor_]

Even the cheapest consumer DACs oversample into the megahertz range.

[speak_on]

The most impactful for noticing the difference? Again, I would argue it's the trained ear. If you have plenty of mixing experience then all these details add up, and a treated room becomes the most critical - agree with that.

[vor_]

So far, here isn't sufficient evidence that anyone has such reliably golden ears.

[speak_on]

Other than the top engineers in the industry. This is a discussion that always ends up in the "double-blind study" vs actual real engineers working in the industry.