I think I get what you mean by sophisticated. If you mean something subtle, not emphasizing too much, gets out of the way but is nice and detailed. Definitely not bass heavy. In which case for me that would be rebuilt Quad 57s by Wayne piquet.
as a comparison the next 4 for me that I’ve owned or currently own would be in order:
Magnepan 3.7
Quad 63
Harbeth super hl5 plus
Sonus Faber Cremona m
Kef ls50
as a comparison the next 4 for me that I’ve owned or currently own would be in order:
Magnepan 3.7
Quad 63
Harbeth super hl5 plus
Sonus Faber Cremona m
Kef ls50