Shadorne, yes, I have heard great things about the ATC products before, but they dont seem to be widely distributed or very well known.
Could you please give more detail on your experiences with them? Which models? Passive or active?
ATC is a UK company that make their own drivers. They have gained fame from their 3" fabric dome mid range designed by Billy Woodman (ATC founder and an engineer). On SCM 20's the dome is grafted onto the woofer. On the SCM 50's they use a less powerful version of their classic mid range the SM75-150. On the SCM 100's and bigger they use the classic studio mid range (very powerful SM75-150S).
My experience is that the timbre is very similar among all models and all have a very wide dispersion with a very natural sound. Piano sounds just like a piano...this may seem like an odd statement but my experience is that most speakers fail this test miserably. Clarity in mid range is never a problem even with movie soundtracks that are loaded with background noises (something many people seem to complain about).
The passive models are not quite as detailed or precise.
The bigger models have more dynamics and are much more convincing (effortless) at live music levels. Generally I hear more detail from the separate mid range (as opposed to grafted on on the SCM 20) and on the larger SM75-150S... I believe this is because of the greater dynamics or crystal clear sound and probably a better bass from a larger dedicated woofer that allows for more lower mid detail to be audible due to less harmonic distortion from the bass. (Nuances and details in the recording become very apparent...some may not like this)
All models can play extremely loud. Relative to the popular consumer sweetspot of loud speaker sound ATC's will seem light in the bass and treble...polite, natural or neutral sounding. They do get overwhelming at high output levels and generally your ears will tire well before the speaker. At loud levels the lack of mid range compression means the mid range level will be what determines how loud you can stand it. (Most other speakers have way to much audible distortion before exceeding what my ears can stand, which means they lack the necessary headroom at normal volume levels.)
Is the SM75-150S the best mid range in the world right now? I have no idea, but ATC have been making this same model since the 70's. It was a big hit back then with UK/Europe/Australian studios for professional applications and still is today. If you check the ATC user list you will see that studios continue to install them.
I have never seen an ATC advertisement in a rag (unlike nearly all their competitors). ATC are unknown to consumers in North America. Word of mouth has recently made ATC popular in the highest end pro studios in the US too, perhaps partly due to British audio engineers that emigrated.
Best Word of Mouth Mid range in the World may be?