assuming excellent engineering of source material, any decent system, and decent speakers:
speaker placement in a room with not too close side and rear walls to avoid too early reflections, listening position close to equal distance triangle, adjust toe in direct for center only, or adjust toe in for a bit wider imaging for 2 focused listeners, (thus: method of moving/marking speaker locations tto change to either situation) and,
balance control, remote from listening position, to instantly fix darn good but not perfect engineering/balance for any individual track, live broadcast, whole 'collection' lps, cds ... with a gaggle of different tracks involving different engineering.
speaker placement in a room with not too close side and rear walls to avoid too early reflections, listening position close to equal distance triangle, adjust toe in direct for center only, or adjust toe in for a bit wider imaging for 2 focused listeners, (thus: method of moving/marking speaker locations tto change to either situation) and,
balance control, remote from listening position, to instantly fix darn good but not perfect engineering/balance for any individual track, live broadcast, whole 'collection' lps, cds ... with a gaggle of different tracks involving different engineering.