Speakers "Disappearing"

Most speakers I have heard would sound much better if they did  " disappear ".

Precise placement of speakers down to 1/4” only works if your own ears are totally symmetrical.  Most of us have ears and eyes where one side is slightly favored by your brain and that’s why you have the balance control.  Also, I have compared two CD players in my system where the same CD is presented slightly differently by each as far as imaging goes which I did not expect.  Experimentation is your friend.

Get them set up well, then make them less conspicuous. I have very open weave sheer silk "slip covers" for my Brystons, in black, and also in color patterns that blend in the room. Either way enhances the "disappearing" and therefore improve the imaging. Psycho-acoustics!

Not being flip but the best way to make your speakers disappear is to close your eyes or turn the lights out. Experimental psychologists have studied the "ventroloquism effect" which is a tendency for the perceived direction of sound to be where the source appears to be, not necessarily where it is. As long as you can see your speakers your brain will be fighting this tendency. This is probably one of the reasons why headphone listening can give such good localisation, nothing visual to distract the ear.  Of course it helps not to have phantom channels and room reflections messing things up too.