Wide dispersion + high efficiency + detail + coherence in a speaker?

And coherence is the biggest point! I like the liveliness of single driver speakers but I am looking for something with coherence AND bass! High efficiency is important for liveliness, and wide dispersion for a huge sweet spot and instruments in the room presentation.

Any recommendations?
A1a8de77 5edc 41cd 81be 1d880e53de83zuio
Vandersteens with built in sub.
Get a pair of Ohm Walsh's! Mine work and sound great pretty much anywhere in the room - unlike box speakers! They act as true point sources and are quite affordable!
No need for a sub with the Walsh's. For more bass just move them closer to a wall!

I think you are asking for too much.  The Ohm Walsh speakers are nice and they are 360 degree radiating, but compared to other speakers, you are going to sacrifice coherence/clarity.  They are not extremely efficient at about 87db.

You could look into MBL speakers with the 360 degree metal ribbon radiators, but you are at a significantly higher cost area, and they are much less efficient at about 84db.  They sound absolutely amazing, though.

You are most likely going to have to compromise one of your requirements.

For a conventional speaker, look for tweeters where the dome extends further out of the surface plane.  This allows the dome to radiate in a wider dispersion area.  An example would be the Morel Supreme Tweeter:


Though, I don't think the Morel speakers are that coherent/clear.  They have a tube-like bloom to the sound.

Good luck.

what is the problem? wide dispersion plus high efficiency 
or wide dispersion plus coherence?

Vandersteens have a tiny sweetspot
MBL are lifeless and are not coherent at all.
Ohms lack in dynamics and detail.
If coherence is truly your biggest point, then you may be better off looking into the idea of designing and building your own speakers. If you are willing to look at something open baffle, then your degree of difficulty will be reduced dramatically - no enclosed box to design, calculate for and try to build...OB can be done much more simply and inexpensively.

But, if you’re looking seriously at coherence then you’d also in fact have to rule out passive crossovers. They can really do a number on the entire crossover zone. They spoil stage coherence, dynamic coherence (by robbing lots of power from the amps) and also tonal coherence which can affect things like clarity, timbre and vocal sibilance and intelligibility.

You will need active crossovers, digital are best...standalone active crossovers that use passive parts are too limited to be of any real value. But Behringer DQX, or Crown XTi-2 amps or the DEQX with the amps of your choice And a good conditioning solution that works for you and you can have real coherence that few other systems are capable of even at many times the cost.

I’ve done all this myself. I went with the Crowns and a buttload of Alan Maher Designs to completely tame the (mostly) digital noise and - presto, it’s all to die for.

Oh, and for wide dispersion you might want to consider excellent quality dome tweeter designs (beryllium??) rather than ribbons. Ribbons may have better detail usually, but they may also tend to beam a bit more than cones or domes.

None of the 3 speakers mentioned/listed would be considered a "High efficiency " speaker (HE). Generally speaking HE would mean a sensitivity of at least 94-95 db with 1 watt at 1 meter and an easy to drive impedance load. Typically 6 ohm load or higher along with a relatively flat impedance curve that avoids dips into the lower impedance range and avoids steep phase angles. Vandersteen has a relatively easy speaker load but has only modest sensitivity (less than 90 db).  There some speakers with 4 ohm nominal  loads that have  generally flat impedance characteristics  and found to be easily driven (examples,  Tekton and Horning). 
I never understand why dispersion Is important to people. When I do any serious listening I sit down and listen. In fact I consider lessxdispersion a good thing as you get less room interaction. If you’re looking for a party speaker, then yes dispersion is crucial. But nobody is critically listening during a good party!
You should should check out Living Voice OBX RW speakers. They are effecient/sensitive with a benign impedience curve. 94db and the impedience does not drop below 6 ohms at any point. In a small room, 12x14 or so,  8 watts is fine. In a larger room 20 - 30 watts will do wonderfully.

They are the most coherent speaker I have owned and deliver uncanny musicality. Wonderful wide sweet spot and soundstage to boot. The midrange is very open and lively with wonderful tone.

The bass while not 20 hertz deep and thunderous is full bodied and present down to about 30 htz. They are rather small and easy to set up in most any space.
Depending on your budget and on the physical size of a speaker that would be suitable for your room you may want to consider the Daedalus Argos. Click on the "specifications" box on the left side of the page for detailed specs.

As an owner of their Ulysses model, which differs from the Argos mainly in that the Argos is designed to provide a much wider sweet spot, I suspect it could very well meet your requirements. I don't know what current pricing is, but as a very rough guess I wouldn't be surprised if it is in the vicinity of $20K.

Good luck. Regards,
-- Al  
Charney Audio horns. I have the Maestro with Omega RS7 drivers. All of his horns are high eff and produce clean articulate coherent bass. Charney utilizes the Tractrix theory in his designs. The horns are rear loaded and couple with the room to produce coherent, 3d,  and engaging music. No sub needed for any of his designs. I have had a number of people in my room (11x15x8) and usually the first response is "How did he (Charney) get such great bass out of a 6.5" driver?".
Zuio - All of your speaker requirements are delivered with Charney Audio Horns.
The Zu line of loudspeakers have nearly all of what you are looking for.  I don't believe they have the wide dispersion.
@zuio --

Perhaps some older Tannoy Gold 15" dual concentric drivers would do the trick. Simon Mears Audio makes Tannoy Autograph replications with these drive units, refurbished and all, and they provide you a uniform dispersion pattern (much more important than "wide" dispersion, I’d say), true high efficiency (~99dB), detail/insight, coherency in spades, and great dynamics and bass to boot. They’re big and heavy, and will cost you at least or about $20,000/pair, but you asked for it without specifying a retail limit, and I’m giving you an example of speakers that may fit the bill according to your needs. Not least, they’re beautifully made from ground up to original specs.

As I recall the larger Walsh models are somewhat more efficient than the smaller ones, like the microwalsh, and overall they are not any harder to drive than most, perhaps easier. Not high efficiency like Klipsch though for example, for sure. OHM Walsh goes for extended bass in a smaller package so cannot be high efficiency.

Also, regarding coherency, I take that to mean clean integration of all frequencies for the listener. That is what OHM means when they talk about coherency with their Walsh CLS (Coherent Line Source) technology. Imaging and sound stage are different things. OHMS/omnis do those differently for sure, especially imaging. The imaging can be very focused when set up right or not so much otherwise.

Omnis and their ilk will probably never be as pin point focused as say a pair of very high quality monitors can be in practice.

The OHM Walshes go for a live like presentation in regards to sound stage and imaging, not a pinpoint one, which might occur in certain studio recording masters, but hardly ever live in real life or in live recordings.
Spatial Audio X2.
I use subs and new Klipsch Heresy IIIs…subs bought used a few years ago (200 clams each…REL Q150e, Q108 II)…with a well sorted pile of gear behind them, the Heresy IIIs are surprisingly coherant…not beamy, especially for horns (phase plugs do work it would seem), and not too expensive (under 20 thousand bucks…YAY…), but you have to have subs for the anemic bass response. I think "live" sounding is sort of an apt description that could have something to do with efficiency (claimed 99 db), and I mix live shows frequently as a hired Knob Turner so for me live stuff is frequented frequently making me a frequency freak for what I feel is accuracy. Note that as a mixer for live stuff I get to impose my taste on innocent bystanders…hundreds of them at a time…I relish the power and it simply stokes my ego until I spend hours rolling up cables and storing gear…at which time I return to being a regular person.
I should say coherency is in fact about the entire presentation,   timbre, soundstage imaging, the whole shebang.   OHM Walshs exceed at all that but as I described not in exactly the same way say as a good pair of monitors in terms of "pinpoint" imaging.   More coherent overall than mbl  but hard to match mbl in terms of sound stage depth and associated 3-D imaging possible there.
ATC Active 40 or 50.  Active means efficiency isn't a factor.  Lots of detail, coherence, dispersion.  The pro 50 is better but the home 40 may be voiced for home use and sound better at low volumes. 
jbl 4435
As the OP goes:

Vandersteens have a tiny sweetspot
MBL are lifeless and are not coherent at all.
Ohms lack in dynamics and detail.

A rather unambiguous way of stressing the importance of efficiency (i.e.: liveliness and dynamics), as well as implicitly downplaying soundstaging/imaging (or aspects of it) compared to other traits - certainly if Vandersteen and MBL are anything to go by in this regard. Single-driver speakers are also mentioned by the OP, and so may point to a desired carrier of coherency here other than liveliness (coherency likely means different things to different people). Options may not be multiple, and some compromises are inevitably to be made. Nevertheless, should be a fun journey.
JBL 4319 monitors. Mine are still breaking in and are still amazing me. Not highly effecient (92db) but 6 ohm and they don’t have to be aimed directly at me to sound wonderful.

The highs can reproduce bells and chimes like they are in the room and have bass that can rattle my windows.

As for coherence and the ability to unravel the music, they can undo Gordian’s knot without slicing it in two.

All the best,
There are Tannoys that have all that, except maybe only moderate in dispersion (which aids efficiency and ease of integration into rooms)
You won’t sacrifice detail and clarity with OHMS if set up right. You will hear it all. There will be so much going on you will just have to decide what to focus on at any particular time, similar to a good live performance. They also compete in coherency with anything. Hence the name Walsh "coherent line source" driver.   Lots of bass.  There are even step up models with built in integrated powered subs if needed.     Set up right, the whole line sounds similar so if your room is small or you do not need the ultimate bass smaller less expensive models will do. 
When it comes to dispersion I think it's a question of whether the off axis response is just lower in volume or whether the off axis frequency response is bad.  When I think of bad dispersion I think of a speaker that has good on axis response but the off axis response is poor.  In cases like this you want to hear as little of the off-axis reflected sound as possible since it's messed up.  If the off-axis response is low in level but the frequency response is still good then I don't consider it bad dispersion. 
Why hasn't anybody just told the guy his hopes aren't realized in anything ever made? 
No one  absolute champ perhaps  but lots of good options that strike good compromises case by case.   I guess thats why so many choices are out there .  I say go for them all. No rule that says you can only have one system. 
For coherence consider ESLs. Like Quads. Not hybrids like ML.
The rule of income constraints means I can't have a bunch of rooms with a bunch of rigs that exploit one or two virtues to their zenith. Consequently, I go fo the virtues that I care most about. Chief among those is impeccable imaging followed by dynamics, which in my estimation goes hand in hand with convincing depth of field. Bass is needed, and it needs to be decent, but reaching 15Hz isn't a priority at all. I'll never use subs. Of course tone and neutrality are critical, but I don't think I put the shameless emphasis on tone that some do. Efficiency.... Not a critical factor. Dispersion is only important in how it influences other factors. 
I'm not looking for a holy grail. I'm looking for what I like. 
+1 on the Ohm suggestions. I have had the 2000s since 2009, and they provide as much of what you’re looking for as possible in one speaker. No, they do not project laser sharp images, but there is image specificity within a very wide, deep and tall soundstage. The bass is extended, solid, and accurate, and they are pretty easy to place. With the right amplification and source material, the dynamics can be nuanced and explosive, IME.  They are not, however, very efficient (~87 dB sensitivity, IIRC). But they do quite well exposing fine detail without becoming etched or overly bright. And they are very affordable (the 2000s are $2800/pr). You can read my full review of the 2000s here on Audiogon in the review section. Over eight years of listening to them and I wouldn’t trade them for anything I’ve heard under $14K. I do run them with subwoofers, and they respond well to improvements in the signal chain (I have upgraded most of my system since I got the 2000s). Forget the preconceptions about omni designs people who haven’t heard the current Ohm Walsh speakers will tell you, and hear them for yourself. Ohm offers a 120 day in-home trial.
Bondmanp +1
++1 mapman! I have a pair of the older Walsh Sound Cylinders (with the 8 inch drivers). In use for 10 + years now! They do indeed sound AMAZING - a wide open 3D sound from anywhere in the room!
I like the JBL recommendation so far.

regarding ATC - wonderful speakers but they come to life only at high volumes.

the efficiency thing is about immediacy! That is the magical word that is important in HiFi !
Coherence and dispersion = Revel. But not efficiency. Efficiency plus coherence maybe Goldenear Triton; anything with the powered woofer (3+ and up). No efficient speaker with coherence and dispersion comes to my mind. Zu may be efficient and quasi single driver coherent but forget dispersion. And frequency response curve is a deal breaker for me. Good luck. If you find a real answer lemme know.
Like previously noted…Klipsch Heresy III…el disperso a mundo.
The Hereseys are a bargain when you look at what $1800 buys these days.   Big soundstage , huge dynamics,  very good imaging, tight bass , clear and clean sound regardless of volume.  Feed them a good source with a good amp and they are hard to beat.

Too bad they aren't held in high regard by most "audiophiles"  , many of which I doubt have even heard them.