A treated room would be the most impactful, DACs the least.
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.
The DAC is pretty impactful if it's outright incapable of outputting anything beyond the usual 48kHz :)
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.