Where to hear ATC speakers

love your detailed requirements list and thoughts OP
the active filters do not sidestep the first order phase issue, they just move the steep slope filters and phase shift upstream
try to go listen to the Quattros, Jim Thiel and Vandersteen cut from same cloth. I own both. and as mentioned get time in front of ATC speakers ( yes the unobtrusive black no fuss models ) in das studio, they certainly have many virtues.
your reference back to Viola unamplified is rare, most people chase tail trying to correct for all the aberations in the chain, including microphones....enjoy the music !!!!!

ahofer

Here is the new beta website for you to see

www.audiodoctor.com/wp

go to about us page and see brands

please note this is beta so it is not done yet

as per Wilson's being fatiguing and image  being too forward that will depend on how they are being driven and setup, the Wilson's are very smooth in the top and so are the ATC both speakers throw a big soundstage.

We had a client runing the ATC SCM 40 MK II on an all Naim rig and the sound was amazing, it sounded like your were in the recording studio with a live band, with the famous punchy warm and full bodied sound of the Naim.

ATC makes a fantastic speaker it will all come down to what you are trying to create. 

Dave and Troy
Audio Doctor NJ ATC dealers

I'm not very technical, but here's ATC's claim:

" Active filters allow independent control of level and phase(time). This is not possible with passive crossovers. With a passive crossover any changes you make to the circuit affect both level and phase. The benefit this allows is that we can adjust for the crossover to have a perfect magnitude response and phase response. The result is that the stereo imaging is much more stable and the tonal balance of instruments is improved. " 

At any rate, as I said, I've heard the active and passive versions of the same KEF, and it's night and day.  And generally, I think the amp-load matching opportunities in active designs eliminate/optimize much of what people hear as differences in expensive amplifiers, right down to the driver level. I remember that Julian Hirsch's infamous blind A/B/X amplifier listening test involved a mediating gain/impedance-matching step that probably fouled the experiment, but I could be wrong. (ducking away from object thrown by amplifier mavens).  I also run balanced, and like the idea of going balanced to the speakers.

For your Thiels I would look for a local tech to look at them, really no reason to send them half way across the country for another tech. If you are just trying to repair them any competent tech can change a failed part. I'd imagine there are quite a few competent techs in NY. Ask your local audio dealer for a recommendation on a local Tech.  

Ahofer, in the case of the Kef LS 50 active vs passive no question the actives are better. 

In the case of a more expensive speakers there are more issues at stake.

You have to like the sound of the amplfication built into the speaker or in cases of actives with dacs then you have to like the sound of that part of the chain as well.

In our shop we never sold that many of the active Kefs because if you went with the passive R5  at $2,800.00 plus a Nuprimce IDA 8 a 100 watt integrated dac the sound of the better passive speakers was far superior and the money was more but not that bad compare active plus stands $2,200 + stands $400 = $2,600

Kef R 5 floorstanders $2,800 plus amp $1,000.00 no stands $3,800.00 factor in speaker cable and you are a bit further but the difference in the size of the image, bass response and overall clarity still points to the better speakers with the external amplifier. 

So you have to factor in will the active 40 do it for you with the very clean sound of the built in ATC amplifiers or would you prefer the passives which you can flavor with a dac/preamp/streamer/amp of your choice such as the Naim Uniti Nova or the new Krell K300i integrated the actives will sound cleaner the passives may be flavored more to your tastes it will come down to a demo to see which way would be best for you.

Dave and Troy
Audio Doctor NJ