Dynaudio vs Harbeth vs ProAc

To quote U2 I still haven’t found what I’m looking for...
Special 40 vs Compact 7ESIII vs Response D2...Considered Ref.3A De Capo BE's but recently heard a BE tweeter and prefer silk and the finish is not what I want...Borderline small/medium size room,well treated and being driven by tubes...Musical taste all over the map with normal listening levels including an occasional ear clearing session...Value decent imaging and staging with an organic tone that allows you to feel the wood of a cello or violin,the stretch and leading edge thump of well recorded drum skins...Not a bass head but need a bit more than current Excite X14’s offer...
ATC SCM19 v2 should be added to the list. It fits the description of what you are looking for. 
I have listened to the Special 40. They are one of the newer models in the Dynaudio lineup. They sound really good, IF front-ended by some very good ancillaries from Moon or Mark Levinson. I have heard them in such a system, wired with Nordost Fry or Vallhala 2. They were playing the Nils Lofgren "Keith Don't Go". So obviously they had to sound good :-)
That said, I took delivery of a pair of ProAc floorstanders today and love them. I have not heard the Response D2, so cannot comment. But based on my experience with multiple Proac loudspeakers, I can imaging they would sound very good. I have even listened to the Harbeths you mention. They are warmer compared to the ProAcs and Dynaudio. Going from cool to warm, here is how I would place them: Dynaudio - ProAc - Harbeth.
Good Luck in your search and I hope you can listen to the speakers in-person.
Value decent imaging and staging with an organic tone that allows you to feel the wood of a cello or violin

You want a Spendor Classic.
I’ll second the proac speakers I always found them very life like. I’ll also toss in another speaker the living voice speakers also from uk very tube friendly and very musical and detailed. 
When I upgraded my system years ago the two best speakers I heard were the Dynaudio Special 25 and ProAc Response SC-1.  I did listen to some larger and more expensive rigs but those were the ones that hit me where I lived.  I haven't yet had the pleasure of hearing Harbeths.
I'm another vote for Proac. I have a pair of the Response 2.5s and there are still very few speakers I would buy to replace my 20 year old pair.  Match them up with some Audio Research gear and you have a match made in heaven.
What tube amp do you have?  Not sure how tube friendly any of these are, but I'm another vote for ProAc.  They image great and just sound very natural.  Another excellent option is the Joseph Audio Prism, and there's a pair for sale here now.  Best of luck. 

For years I drove Response 2.5s with a 14W Cary Class A SET 300B amp, and never lacked for power.  Don't know if the later generations are equally forgiving.

Interesting to read all the positive comments about Proac. I have 20 plus year old mint condition Response 3.5s with Audio Research electronics. I’ve been shopping for new speakers and have heard the Paradigm Persona 3 and 5, KEF Reference 3, Wilson Sabrina, latest Proac floor standers and others. So far I’m liking the KEFs. Still planning to hear the Ryan Tempus 3 and possibly the new Magico A3 if available soon. All the positive Proac comments make me wonder if I’ll regret selling my Response 3.5s and spending the extra money for the KEFs (or the others). Any thoughts?
@fast Hard to say, but as I was changing speakers around I owned quite a few different brands including Joseph and Harbeth, but ended up back with the ProAc D-40r. The new ribbon tweeters are so well integrated and natural sounding it is tough to beat, especially if you are used to the ProAc Sound

I second the atc scm 19 v2...they dig into material like i have never heard before...with an honest tonality...if you appreciate quality over colored up tone youll like them...I believe that they are a bit of a bargin...if you can buy used 9's/10 even better. 

They need power to get them sounding there best though!

I have a slight preference for Harbeth over Proac but both are quite good. I agree with jpjerry Proac ribbons do sound very natural I was quite surprised when I heard them.  Dynaudio I've never heard but they are typically harder speakers to drive and not as well suited to tubes.
@fast Check out @milpai's threads on his quest.  Ended up between Spendor D7/9 and ProAc, and he went ProAc.  If you're anywhere near New Jersey, be sure to visit audioconnection
Those are 3 brands in which I've been interested over the years.

Initially I was high on Dynaudio because I'd heard them sound really neutral, controlled, etc.  But since then my encounters with Dynaudio speakers leaves me with the impression "boring."  Purely subjective of course, but there is something almost neutral to a fault about their sound, for me.  (And I normally like neutral.  I don't care for obvious frequency bumps and humps, and my current Thiels are superbly even and uncolored in that regard.  But instruments and voices sound more rich and organic through them, vs what I've heard from Dynaudio which always remind me I'm listening to a hi fi system).

I've always enjoyed the Proac sound but, as with Totem speakers, I usually find the sound to be a bit too obviously sculpted for long time enjoyment.  Just a bit "pinched" below the presence region, a bit of upper frequency spike that gives transients some excitement and clarity sitting on a bed of lusher mids.  A very nice sound to visit, but as I said, I've always found it a bit to "obvious" for me to desire those speakers.

That said, I gave Proac another chance recently....I've just forgotten the exact model number but it was modest sized floor stander with their new ribbon tweeter.   For me the ribbon tweeter of the Proac just stuck out pretty obviously.  And it's not that surprising given the speaker had to my ears that slightly sculpted upper frequency range to begin with.  There was an overall more icey character to the high end in the proac that left me cold.

I ended up with Harbeth Super HL5Plus speakers for a while, recently.
They sounded simultaneously "lush" and "neutral" which is quite a feat.
With a special roundness and softness for voices that is hard to find in any other speaker in my experience.  I can hear some of the box (or it seems to me I can) in the Harbeth sound, but it's a beautiful, organic, seductive presentation that draws me in.

In the end I preferred my Thiels, which to my ears sounded cleaner, more dynamically alive, realistic, but without sacrificing smoothness and body.

That's all darned subjective stuff though and should be taken with a heavy grain of salt.

Another vote for the ATC SCM19MK2. I still have the MKIs and love them. So natural and transparent. If the rest of your chain and room are in good shape, try to hear them.

Having heard Dynaudio, Harbeth, Proac and others over the years, I don't think they have much to offer over ATC, from my ears.

Other brands I would throw out there for natural mids are Totem, Aerial, PMC and Living Voice.
Well I found myself in downtown Seattle yesterday and managed to put together 5 hours of speaker demo's..Heard the C7ESIII & PMC .22 I think it was,both driven by Primaluna...Harbeth was HUGE coming from Excite X14's and with some of my music just seemed a touch too civilized and the magical midrange about the same as the Dynaudio's,not for me..PMC's showed me how TRULY WONDERFUL the Excite X14's are..
In another store I heard the Special 40's driven by a SimAudio integrated and again was gobsmacked at how good the little Excites are.I see moving to the S40's as a slightly sideways move so their also out of the running..Going through the rather large selection of used gear I listened to a pair of Kestrel Hot Rods and Response 1SC's but the real jewel was tipped over sideways and covered in dust.A pair of Nola Boxer's(original series)...The cabinets were beat to hell but the drivers were perfect so I gave them a listen with the Primaluna and oh man did they sound good...Just enough of what the baby Dyn's do with a dash more of the golden glow I'm looking for..Not quit enough bass and the treble isn't as sweet as the Excites so I'm looking hard at the Boxer 2(NOT the 2s)which in my room should hit a solid 40hz,work perfectly with my amp and the stands I already have and offer more of the sweetness on top and better resolution with the series 2 drivers...
 Now waiting on Nola to see if there is a stocking dealer anywhere near.If not I may just order a pair based on reviews and what I heard yesterday...
Just after posting update above I got a call from an honest to goodness brick and mortar Nola Dealer about an hour south of me.I had seen a demo pair Boxer 2 listed on his website and left a message expecting a call during business hours Monday.
 Sorry but the demos were sold..Since I was a 2 hour trip away and since I would have to wait a week or so for delivery Burt(owner)offered my choice of finish(Gloss Cherry),new in sealed box at the demo price!!!Done deal!Gloss Cherry Boxer 2 INCOMING!!!
 I can not wait to hear them with the Quad amp,I have a feeling I might finally be getting off the merry go round(well except for finding the perfect headphones now)...
Congrats on your new speakers I'm sure the anticipation is killer! Never heard them but at one point I had a pair of Alon, Nola's previous name, Lotus SE's that I quite liked. Happy listening!
Congrats. I've heard some Nolas before and thought they were good! Enjoy