There is only one placing that is optimal. The typical zone of neutrality is a good approximation but getting to the millimeter is a real trick. Dave Ellington (Wilson Audio) who knows a thing or two about set up heard one of Todd’s XVX/Subsonic set ups which was previously set up by Peter. Peter had spent a lot of time getting it to his liking. It was so much better that after one song that he stood up, turned around walked to the back of the room and shook Todd’s hand saying “GREAT set up man!”. The last inch is a football field in sonic terms. There is SO much to this. No one can fully explain it on a forum like this. Elliot is right you first have to know where you are going and you need really good listening skills and you need a LOT of experience. Lots of people can get close and you would never know what you’re missing.