This will take some A-B which there is plenty of it with AG vs. Zu but Coincident is gonna be tuff, I have heard all three, my favorite speakers for years was the Duo's, just to much money in comparison to the def's, which if you do some research beat out in many peoples eyes and ears the Duo's, however I have never heard an A-B of any combination between these 3, all different rooms and systems...
The coincidents are sweet pieces and for the money might be in the top range of value, but depending on your taste and how big your room is, or how far away you can listen will be your main concerns using any of these 3 speakers...If you want Zero compression at levels that approch insane, then the AG and Zu are obviously top of the class, but need a big room and pretty decent distance, however the Zu's will work far easier in placement issues than the AG's, every report on the Duo's are about absolute perfect placement and you need some distance from the sidewalls or you are in trouble. When I heard the Duo's in an excellent system(they were set up in a mansion) and were at least 12 ft off each sidewall with about 9 ft between, or you would get a lot of problems with those horns to close to barriers it seems. The Zu's I first heard in a Huge room as well and quite literally sat nearly 30-35 ft away and they were beyond amazing. The coincidents are guaranteed probably going to need tubes, and so will the Avant's, However Zu can definatly get away with some of even the lower end solid state and better designs. For versitility overall look at Zu and Coincident, Coincidents seem to give maybe a little more intimate sound, might be "Romantic" as people like to say, but will not keep up with the explosive openess of the other 2 speakers, in a well treated room with super smooth electronics, then the Zu and coincident again will be the choice I believe. Avantgardes are someting a bit different, and might pose some bigger obstacles to fully enjoy and to some extent are a bit pricey in comparison to the results vs. the other 2. I believe 6moons.com is a place to start on this, I think going thru their Archives they have results of all 3 of these speakers impressions thru some common reviewers.
Sorry for the Ramble.
Of the speakers on your list, I'd choose the Avantgarde Duo, or if that wasn't possible then the Uno.
I would go with Zu or Beauhorn over Avantgarde-From what I hear, uno and duo owners all prefer the trio if only they could afford them-and many trio owners have switched to the Beauhorn to get off the endless upgrade track and do away with the driver intagration problems all together. Now I don't want to degrade the Avantgardes too much but the value issue is something I cannot get over.
Consider the Merlin VSM, and Verity parcifal's as well.
The TT has great detail, even at low level.
I have no experience with the mentioned speakers 'cept the Definition 1.5s. Wonderful detail at very low volumes. I run mine with an Audio Sterling Premier integrated. 18 SET watts to die for. From my experiences, as well as many others, the Defs can be brutal on SS. My Definitions are almost fully broken in. Electrostatic speed, midrange to die for, and the highs are airy, light with excellent dispersion. You may not find these results with your amp. I was told early on, that the Defs are very sensitive to amplification: may be more important with these speakers than the source. The absolute most enjoyment I have ever had from a speaker since my Magnaplanar Tympani 1D days. peace, warren :)
The Zu and AG have powered bass modules which may not integrate as well with the other drivers. The size of your room and listening position is also a consideration.
I would be foolish of you to buy any of these based on recommendations here. You need to listen to them and decide for yourself. Travel if you have to with your Pathos in tow.
I have to strongly disagree with undertow. The Definitions will not deal well with low end SS. In fact they might not deal as well as you may think, with the very best that SS has to offer. The Defs are very unforgiving with SS of the highest quality. You did say that you're looking for "micro detai at low levels." If you're thinking Zu, think SET. 101db!! You'll never look back..
I'm using my Def's with a battery powered tripath amp that is very nice with them. When I was using a tubed pre, it was heavenly. But, heaven must not be good enough because I've gone to SS which has tipped the balance to clinical. A 45 SET amp is en route. . .
I have heard the Duo's and Def's on a 700.00 Exposure intergrated 40 watt per channel, and it was excellent, not the best but excellent... However I will say that Tubes in the chain are always nice Period! A sweet tube pre with good but resonable priced Solid state like a mccormack, or the new First Watt amps are no slouch either.
Writers claiming that Zu speakers do not work well with solid state gear simply don't know of what they speak. I'm running a pair of Defs with both Art Audio PX-25 SET mono blocks and Pass XA-60 Class A mono blocks. The Definitions sound marvelous with both; there is no "clinical" or "analytical" character with the Pass amps. Actually they do a substantially better job at the bottom end (40hz-100hZ) than SET tube amps. Unless the previous posters have tried good solid state amplification it is both unwise and unfair to dismiss it.
I forgot to clarify, LOWER cost like 800-1500.00 used or possibly new solid state amps can work well with Zu, even people these days are using the Nuforce 1200.00 mono's I guess with very good results. Sorry to offend the tube God's, but I do always agree a good tube pre is needed.
I run my Druids with a HT receiver as the preamp and Flying Mole 100 Watt SS monoblock amps (modded with Hexfred and Cree diodes, better coupling caps, better binding posts, bypassed volume controls, etc.) and they sound very good to me. But I'm planning on getting a Modwright 9.0 tubed linestage to replace the receiver very soon. Should sweeten up the system considerably, but it's no slouch right now. The Flying Moles are very nice amps for the money.
My Druids began life in my home with a PS Audio combo, PCA-2 and HCA-2. I understand the HCA-2 is one of the amps in the Zu boys' stable. While I like the amp very much as a value for money, I felt it did not do the Druids justice, and have since moved irrevocably into tubes. It's interesting about the sound; when you are listening it does not feel like it is analytical and in fact feels a touch warm. But change amps and the speaker communicates the nature of that amp right away; it is shockingly obvious. I have tried 6-7 tubed amps and each time their nature has been clearly revealed.
Taksil , your Pathos can be perfect for any of these speakers, 30 watt solid state output will have some nice slam to it vs. completly tube at that price.. so don't be afraid to try the solid state on them, and you have some tube flavor on the input anyway of that intergrated, could be a perfect combo for any of the speakers in this hi-efficiency you seek!
And I actually don't remember where I found it, but They did compare the Victorys to Duo's stating the Victorys to have a superior integrated Bass to the Duo's, but found the dynamics more explosive with the Duo's.. And They have compared the Duo's to the Def's basically the Def's won out by far in the bass as well, and many other catagories, but If you can't hear any of these speakers for yourself you could make a mistake taking a leap of faith on a used pair of any of them on audiogon if thats what you are asking.. Of course I see no Definitions up for sale ever, but there are a couple pairs of Victory's and several Duo's all the time.
Undertow is way off base in two regards - since horns have limited dispersion, they are actually LESS sensitive to sidewall reflections, and in fact have GREATER placement flexibility than speaks using dome tweeters. Secondly, although tubes are the classic match with Duos, Avantgarde makes solid state amps which reportedly (and not surprisingly) mate very well with the horns. With excellent amplification (I use Lamm ML2s), the Duos positively sing at low levels...but you'll have to fight the temptation to crank them up due to their vanishing distortion levels.
Thanks to all of you who have shared your knowledge and experiences. I will keep you posted on which system I end up with.