Horn based loudspeakers why the controversy?

@johnk 
You're making a bunch of unequivocal statements there that I can go out and prove wrong right now with the cold, hard evidence of measurements. I glossed over a variety of horn measurements just now. None of them have dispersion as even as my Focals, much less something like a Magica S5 Mk. II. Horns CAN image well, but do they generally? Not in my experience. I've never heard anything image as flat and 2 dimensionally as horns. I'll allow for a better optimized horn to image well though. 
Somebody correct me if I'm wrong, but dispersion tends to dictate the quality of imaging to some significant extent. I've thought it to be common knowledge that narrow baffles and smaller drivers yield wide dispersion and resultant impressive imaging. I'm not at all surprised to find that virtually every horn I could find measurements on generally exhibited the same truncated dispersion. That's the natural result of simulating a very large radiating area. That's what horns do. I do NOT think that sounds good. It appears judging by the marketplace most people don't think that sounds better or even good either. 
The bottom line is that until I hear a horn that sounds like a point-source I'm not going to like them. Actual sources of sound tend to behave much more like point sources than large, focused, radiating areas tainted with the coloration of an acoustic transformer's resonance and shape. It's kind of like amplifiers with coupling transformers. Some folks like them, some think it's just another contrivance between them and their music. I like DC coupled amps. I like dynamic driver speakers. I don't like transformers of any sort except big toroidals in my power supplies. 

John, do not waste your time anymore with Kosst. I can say, easily, Focals, are not my cup of tea. This is what makes this a fun hobby, and quite a personal and individual one. It is all about the recorded music, and what each of us wants. Once someone starts to argue, or, try to make a point, about their equipment, and that they are right, it shows me, that they doubt themselves, and their selection of equipment. 

Horn hate is just sour grapes.

A great horn system requires the space.

It took me months to find my 21' x 37' listening room

@kosst_amojan

You’re making a bunch of unequivocal statements there that I can go out and prove wrong right now with the cold, hard evidence of measurements. I glossed over a variety of horn measurements just now. None of them have dispersion as even as my Focals, much less something like a Magica S5 Mk. II.

Being anything less than outright experts on the matter I’m guessing most of us here are really just blundering novices, and so are easy prey when we try and read up on these complicated affairs more or less sporadically as a theoretical means to back up an argument. What we should really go by in any final instance regarding sound is that of actual listening experience to account for, in this case, the imaging capabilities we’re after, or as they say: the proof is in the pudding. As things often develop though meanings become muddled as the source of reference has a tendency to be slightly altered over time, but occasionally with severe effect. For, what it really says is "the proof of the pudding is in the eating," and this makes quite a difference to support my claim: we can’t come by our objective just by reading the recipe (i.e.: measurements) to know of pudding and its actual taste; we to have to eat it (i.e.: listen) to truly know what we’re dealing with sonically.

Horns CAN image well, but do they generally? Not in my experience. I’ve never heard anything image as flat and 2 dimensionally as horns. I’ll allow for a better optimized horn to image well though.
Somebody correct me if I’m wrong, but dispersion tends to dictate the quality of imaging to some significant extent.

(and now I’m the one to be theoretical)
Controlled dispersion, or the nature of directivity of horns typically involves the acoustics of the environment to a lesser degree compared to direct radiating speakers, and so in theory you have at least a different, and likely more controllable means (like, at window to a source) to assess the nature of a recording. The more dispersive nature of direct radiating speakers opens up a can of worms in a different direction, so to speak, involving the acoustic environment more highly and so being more dependent on it, but can yield excellent though different results into imaging. Both of these characteristics of dispersive nature are viable, different ways to achieve great imaging, but personally I prefer the typically denser, less carved out and sphere-like imaging style of quality all-horn speakers. From my chair they emulate the live acoustic presentation more closely, and simply sound more natural. As I’ve stated earlier my own all-horn speakers image really well, and don’t cater in any way to the narrow-baffle school. As Kevin Fiske says it, just as an example:

As a rule I can’t be bothered with all that nonsense about soundstage depth and placement – it’s musicality and tonality I want, not a sonic hologram – but the Ucellos simply won’t be denied; a hologram is what they throw, and it demands attention. Sit right in the narrow sweet spot and they project performers with a chiselled-from-granite confidence that is so mesmerising that I temporarily forgot what I’d come there for.

https://www.dagogo.com/simon-mears-audio-ucello-3-way-horn-loudspeaker-review/3/

I’ve thought it to be common knowledge that narrow baffles and smaller drivers yield wide dispersion and resultant impressive imaging.

To my mind this is a marketing ploy. I’m not saying this segment of speakers don’t have the capacity to potentially image well, but it’s hardly a prerequisite to come to fruition - per the above. If anything the narrow baffle design is an industry paradigm with great inertia, and as implemented in the listening room rarely offers solace in regards to the space they take up, requiring mostly to be placed well into the room away from walls. So much for WAF-factor..

The bottom line is that until I hear a horn that sounds like a point-source I’m not going to like them. Actual sources of sound tend to behave much more like point sources than large, focused, radiating areas tainted with the coloration of an acoustic transformer’s resonance and shape. It’s kind of like amplifiers with coupling transformers. Some folks like them, some think it’s just another contrivance between them and their music.

Whatever you like I’m not going to argue, but it’s how we may go on to rationalize and conclude (and not least reduce) on our findings that I see potentially problematic. "Actual (point-)sources of sound" are so whether their origin is direct radiating units or horns, but I think I see where you’re heading at. The need for "point-source" sound to my mind and ears would dispel with the plural and equate striving for ultimate coherency as if originating from a single unit per channel. As such I find my own horn speakers to excel, being that the "large, focused radiating area" - as you describe it - gives the sensation almost of a "mono-bubble," but with stereo information in it (and perhaps this is your issue?). The "mono-bubble" to my mind compares successfully to a live, holistic event, because while instruments play to the left there’s no division of the space into left and right or other; the medium that carries the sound is indeed one large space, and it centers the experience as one of wholeness. Lastly, I don’t see quality horns (as the acoustic transformer) "tainted with coloration," but some may conclude they are marred by coloration simply by virtue of giving an overall different presentation compared to direct radiating speakers. And of course, your overall experience may simply have been one of listening to colored, incoherent horn (i.e.: hybrid?) speakers, and we sure know they do exist as well.

I came into a celebrity's JBL Paragon 25 years ago along with a vintage Mc275 and Mc240. Similarly, 13 years ago I was given 2 Mc2105s, and a Mr77.  I added JBL 2405 slot tweeters (alnico) to the Paragon, and use a MEN220 Room Perfect with its electronic crossovers, biamping with the Mc275 - top, and Mc2105 - bottom (made a huge difference).  The most recent addition is a Bryston CP 26 Preamp (great improvement).  Most of my friends are musicians like me, and none fail to be blown away.  However, when live music plays a prominent role in your life, no speaker does everything, and one can enjoy many different brands and models over the years for their own special characteristics.