Wide baffle speakers are better than narrow

"I’m thinking of every thing from the wide-baffle Arnie Nudell Infinity and Genesis to the Sonus Faber Stradivari here."

Even Arnie learned as he gained experience. Look at the baffle for the mid/high panels of the IRS Betas. Also look at the work of Siegfried Linkwitz.

Super linear constructive and destructive interference amplitude averaging machine.
super terrible time and phase deconstruction machine.
also the flat baffle is a flat horn aka the room up close, writ large. The big negative curved Infinity baffle is a special case and a special speaker and a bearcat to integrate with the room, the bass towers - could be maddening, ask me how I know.... we sold everything but IRS

In my jbl bibles it shows how to construct and brace 4x8 sheets of plywood beside the speakers for behind screen. I would imagine it has to do some with efficiency . And no in wall speakers  arent a go to. Unless you like the sound of plastic and drywall with zero placement adjustability.  

If baffle means the front width of the speaker, I recently came to a decision on the speaker I will get. It was between thin speakers,

Paradigm Persona 3F
Vivid Kaya 45
TAD ME1

and a big fatty.

Yamaha NS 5000.

My search took me to the Magico A3 first and then the Paradigm Persona 3F. I liked the Persona better because the top end seemed better integrated, the Magico A3 was still very good. Both Persona’s top end drivers use the same material (Similar to Yamaha NS 1000 from the 1970’s).

When I heard the fatty Yamaha NS 5000 I liked the sound a bit better than the Persona. The Yamaha uses the same driver material for all 3 drivers, including the large bass driver. I figured I liked the NS 5000 speakers because of the same drivers but maybe it was because it was a fatty and the others were skinny.

Along with Onhwy66, I’d say it depends on speaker design.

Narrow/wide baffle is not always better one way or the other. From my limited experience, wider the baffle, the more easily distinguishable point source for frequencies above the wavelength of baffle length. Another way to say this is, the lower the frequency, the bigger the baffle can be without the brain being able to distinguish where the sound came from.

Wider baffle doesn’t equal better live sound - examples; MBL, Ohm-Walsh, Kii, LXmini, Gallo, etc. Musical instruments themselves radiate in more directions than toward the audience. Furthermore, venues add their own unique sound, none of which has to do with sound radiating directly from instruments.

Live music is typically captured by numerous mics spread throughout a venue, and in many cases directly from instruments. So that conglomeration of tracks gets mixed and mastered. If the sound was captured by a wall of microphones, then I might have reason to agree.

The theory that live music sounds better with wide baffle speakers seems questionable. I would agree that the larger the baffle, the more likely it is for the brain to distinguish where the sound came from - unless it happens to be the resonant frequency of the eardrum or room (or to a lesser degree an ordered harmonic Fs...n of that resonant room frequency).