Speakers design in relation to room ...
For headphone the amplifier/pre which play the second role in creating a better virtual speakers/room soundstaging impression may appear more important. But even with headphone the acoustic design of the shell cup and his acoustic content will be the first factor. The problem is most headphone do not have acoustically well designed shell/cups nor any resonators tuning inside as my K340... ( i dislike generally headphones because of the "inside of the head soundstage" because of their lack of shell acoustic room tuning among others factors for sure ) 😊
----Then Speakers/room as no1...
----Amplifier and preamplifier No2
----Dac design as no3
Speakers /room are always the main factor but this fact can appear to be reversed or contradicted in favor of number 2 or 3 in each specific situation with a specific gear pieces and a specific owner situation and history and needs ...
But at the end we cannot replace acoustics principles as the first rule with historical relative impressions of each different listeners in his specific constraining situation as the rule...
Speakers/room relation is the main factor nevermind our anecdotal but very real for sure gear dependant impressions ...
What i said is true for our usual classical owner of stereo system situation ...
But the crosstalk disruptive effect of any stereo system cannot be cured by speakers/room relation only nor any other classical gear upgrade.
We must buy the BACCH filters to improve not only soundstage dimensions and impressions but localisation of sound source and listener envelopment, then immersiveness.
«Dr. Edgar Choueiri, a plasma physicist and Professor of Princeton University, delved into the world of 3D audio with one mission: crack the code on cross-talk cancellation. Within his research lab over the past decade, he was able to perfect cross-talk-cancellation of two loudspeakers to produce true 3D audio that replicates any binaurally recorded or virtually constructed soundscape perfectly. »