This is a subject close to my heart. I obsess about soundstage. My first point is a bit annoying but I have to say the source and the amplifiction are contributors. As for speakers: in my opinion they contribute the most. Here is my 'Profound Statement': Directionality is overwhelmingly a function of treble. So high quality speakers with tweeters that do 20 khz comfortably are a must. Tweeters beyond the theoretical limit are (in my humble opinion and contrary to others) a benefit. My current position is that the overtones of instruments beyond 30Khz is relevant to directionality. So in theory and my practical hearing means I try to buy between on 48 khz and 96 khz. 44.1 khz is fine. Vinyl is fine too.
All this from a pettifogger. I have Matrix Audio DAC, EMM Pre, Pass Power, Magico Squeakers.
All this from a pettifogger. I have Matrix Audio DAC, EMM Pre, Pass Power, Magico Squeakers.