N.P.I. What is it?

I have always preferred the mono presentation.

Particularly more convincing compared to stereo recordings that mix vocals on one channel and instruments on other. Prevalent on older releases, which the majority of my listening comprises of.

Listening to a mono recording with just one speaker just makes me wish the speaker was in the center of the room. I tried this years ago.

Other than not hearing certain recordings with particular L/R panning effects I could live without "stereo."

One major negative- having a single speaker in the middle of the room looks odd.

All Classical, Jazz and most Rock in mono would be ideal IMO.

Hearing a mono recording from 2 speakers compared to just one in the middle of the room produces a fuller, more realistic sound to my ears. It is also the "parlor trick" of making your speakers "disappear."

i think the preference of hearing mono from a single speaker and stereo speakers is much related to how acoustically dialed in your room and speakers are. and specific set-up differences. so the variability of results will reflect room differences.

in my case i have a 4-tower speaker system and need both bass towers to be working to get full frequency coherence. plus the room is really dialed in so my phantom image is epic. not all phantom images are created equal.

i have two arms with mono cartridges (Miyajima Infinity 1.0mil stylus and 0.7 mil stylus) and listen to a fair amount of mono vinyl and digital. love the mono, both early wide grooves and later stereo cutter head mono’s.

Due to my hearing loss, I have my two speakers just 3 feet apart. Not quite mono and not quite stereo. Let's call it Moneo.  😁

BTW what is NPI?

I would have agreed with the OP until yesterday. I recently re-setup my room and moves the speakers much farther apart. I listened Smokin at the half note by Wynton Kelly Trio featuring Wes Montgomery. I was transported to the Half Note with my Dad who was listening with me. I'd never experienced anything like it. Didn't have that tunnel of sound I used to experience when my speakers were only 7 feet apart. I would concur that some of it has to do with setup.