Now that I've a few days to listen to the ATC's, I can report they are a remarkable set of speakers. They are quite different in character from my Dynaudio Focus 360's, or the Tyler Linbrook Signatures I recently sold.
The various reviews I've read were all very glowing. Many of the reviewers mentioned that they have more of a "pro audio" sound, as opposed to a audiophile sound (whatever that means?).
They have a lot of strengths.
- The dispersion is very wide, not real need to worry about having to sit in a sweet spot to get the most from therm.
- They were easier to integrate with the subwoofer than the ported speakers, due to the infinite baffle design.
- They definitely can play louder than most other speakers on hand without sounding congested.
- They sound very neutral throughout the frequency band. No real emphasis on any one frequency band is noticeable.
- The distortion characteristics from the ATC's are amazingly low. It's something that really jumps out at listener when playing back music. I wound up extending listening sessions due to the performance from the speakers.
- Dynamics are outstanding. The macro and mico detail presentations are very balanced. The presentation is like sitting in the center of of a symphony hall.
Rather than post audiophile jargon, just wanted to cut to the chase on how they sound. To me, they are at or near the top at their price point, and would easily put them up against speakers a several times there price point. The drivers are vey good, especially the midrange driver. The cabinet work is excellent, quite solid.
They do require a fair amount of power to get them to sound their best. They need at least 75 to 80 watts in Class A AB.
There was a review on the ATC's where the reviewer stated the Purifi module did a poor job driving the bass. They recommended to not use a Class D amp with them. I'm using a Devialet Expert Pro 1000, which has a Class D current output, and Class A voltage drive. The Expert Pro 1000 has no problem driving the ATC's, because of the fact it's 1000 watts @ 6 ohms. The Speaker Active Matching (SAM) with Devialet supports the ATC, which safely extends the bass of the speakers. The Expert Pro/ATC combination sounds extremely good, could not be happier with the sound from this setup.
Also tried the ATC's with a tube amp setup, which has 90 watt mono tube amps. That also sounds very good, with dynamics not as robust, but a more lush midrange.
In conclusion, the ATC SCM 40 V2 speakers are most highly recommended. The active version is also well worth looking at as well. If I didn't already have the Devialet, would have given the active version serious consideration.