I used to own planar speaker... those tend to be the ones that are that sensitive to really minor adjustments. I use a laser measurer... and then the sound can literally snap into focus.
Dynamic speakers tend to be less sensitive.
Tweaking Your Speaker Placement
"Depending on the speakers an 1/8” move in the right way can have a significant impact."
What I am curious about is how one can verifiably move a speaker exactly 1/8th of an inch? My speakers on stands weigh about 60 pounds each and being bookshelf speakers, they are a little top heavy. They are also on IsoAcoustic Gaia's, which don't really slide too well.
How do you do it?