N.P.I. What is it?

I agree that an epic phantom image is, well... Epic!

What more can be said about that? It is definitely room dependent.

For another "parlor trick" try this. Listen to a MONO recording on two channels with one of them being of opposite polarity. What happens to the phantom image then, and why? Can the information gleaned be used to help dial the room in? How?

For the best of parlor tricks listen to Cognac, "The Blues Is Alive And Well" Buddy Guy (2018). In stereo of course!

I Love the Blues!

Addendum:

One thing is certain, N.P.I expands your seating options. I agree with elliottbnewcombjr.  

I have changed my mind about preferring the speaker in the corner (R in this case). I like the freer sound of the other speaker.

Surely you analog buffs might have additional reasons for preferring one channel over another?

How do you know if you are an audiophile?

Do you close your curtains in the Spring because you think your system sounds better?

MONO amps make N.P.I. easier.

I am surprised that there have been no takers on the previous mention of polarity. I'm now listening to "Head Hop Rag" JSP 77196 (2015) and not only does polarity make a difference but I have a preference - unfortunately it's not the same for every track!

Speaking of mastering quality, Head Hop Rag and Delta Blues are FANTASTIC!

Head Rag Hop. Sorry.