@shadyJ I had similar discussion on AVS Forum but see I am unable to understand what makes the KEF have that depth of field to it which other speakers I compared to it lack. See I did compare them in the same acoustically treated hall. There the KEF R and to some extent Focal Kanta had the depth of field where I could easily notice the dimensionality and get the enveloping effect. Which speakers like Polk Legend, JBL Synthesis HDI-3000 and B&W 700 series lacked. They were all really good in producing direction sounds and imaging. Like I was clearly able to distinguish the different elements and where the were placed but kinda on a 2D layer. With KEF and Focal I got that feel to which was a bit closer to me and which was bit away and where the elements were exactly placed. Why are those speakers lacking in depth why do they sound flat or why does KEF has that much more depth of field. If they were in different rooms or different setups then yes would have considered that it was the room or setup that made them sound flat. But in same condition KEF was doing something that the other three were lacking. People say it is due to it being concentric driver but then I also had this discussion in JTR thread which also has coaxial driver from highs and mids and there they stated that speakers like JTR and Ascendo even though being coaxial are narrower in dispersion and for a similar effect I am looking for I be needing more channels or would face similar issue as what the Polk etc had.
I am trying to understand this concept. Please your insight on this be really helpful.
You have asked a complex question.
First of all the speaker is only half of the equation. The microphones and their layout, are half or more of the issue. The biggest problem is too many microphones. This bedevils the pop culture, but in that arena, I think having the music in your face is a desired result. At least I think it is, but I run a mile from the pop culture. I do know that for recordings in the classical domain, my view is the less microphones the better.
When it comes to speakers, depth of field really comes down to dispersion and frequency response.
The wider the dispersion the better for depth of field, as long as the dispersion pattern very closely matches the axis response.
Even small peaks in the midrange will destroy depth of field, yes just destroy it. The critical area to avoid even small peaks is between between 1.5 and 5 KHz.
I slight dip here, known often as the "BBC smiley", will give you depth of field bt at the expense of detail and clarity. But a dip is far preferable to even a small peak.
The KEF speakers you liked have a really flat response across the midrange. So that is probably why you like them so much.
Unfortunately the majority of speakers are actually not very good. Gems are far and few between.