Introduction

ARC, or Anthem Room Correction, has been a long time in coming.  Its origins can be traced back as far as 1990 to research conducted at Canada's NRC (National Research Council).  Under the supervision of Floyd Toole, the NRC had previously performed landmark research into loudspeaker performance.  Statistical analysis of controlled listening tests showed that there was a common thread among speakers which subjectively “sound good”: in an anechoic chamber they were the ones which measured a neutral response, free of coloration.  This research literally launched companies like Paradigm who, rather than vaguely poking at speaker design, now had a solid definition of what exactly made a good speaker "good".

On the heels of that research came the “Athena” project in 1990.  Whereas the previous research looked at many different speakers, Athena looked at only a handful of speakers in many, many different rooms  Here again, a common thread was found between what statistics showed to be good sounding rooms.  I'll jump ahead just a bit and tell you that it is not what you'd think.

Armed with these data, the next step would be to create a system which could shape the speakers' response to get the system sounding more like the preferred rooms.  It was only a matter of time, over 10 years actually, until DSP power in audio processors was up to the challenge, and a filtering system capable of the incredibly complex task could be put into play.
 

What's in a name?
 
The term Room Correction, though ubiquitously used in this context, is unfortunately not the industry's best choice.  Room Compensation would be far more accurate.  A small distinction of semantics, but a necessary one.

Going back about a decade, several early automated EQ/filter systems were billed as “speaker correction”, which is not a bad way of describing it, since you are in fact changing the signal to the speaker and consequently what comes out of it.  The trouble with that name was that it made the feature quite unpopular among audiophiles:  no one likes to think there is something “wrong” with their speakers, which needs to be corrected.
 
Since that time, there has been a growing cognizance among consumers, especially the more serious enthusiasts, with regards to acoustics.  It is now undisputed that “the room” has far more influence on system performance than any piece of the system's electronics.  It is my own adage that if forced to make a hypothetical choice, I would always rather have a modest hardware setup in a room with good acoustics than have state of the art hardware in a poor room. But addressing acoustics ranges from the inconvenient, to the expensive, to the downright impossible.
 
It is small wonder, then, that these new automated filter/EQ systems have now consistently, though in my opinion decievingly, been billed as “room correction” by just about everyone.  Unfortunately, marketing departments have pushed forth the notion that by simple application of a filter, the room somehow magically disappears and you are transported to the likes of Dolby or Lucasfilm’s own state of the art mixing facilities.
 
Simply stated: that is not happening.
 
Without thinking too much about the issues involved, it would seem plausible that if you take a measurement of the system's frequency response in the room, and then apply a filter as an inverse of that response, everything would null out and audio nirvana would result.

There are two problems with this sentiment.  The first is that it only works that way for one person and one person only, with their head in a vice at that, since the effects of the room change according to your position in it.  The second is that the room does not disappear.  You might change the sound coming from the speakers, but that sound is still bouncing around.  You can't stop late arrivals and decaying reverb with electronics.  Acoustical treatment is the only way to actually alter acoustics.

Room Correction is not a substitute for addressing acoustics (nor is any other automated EQ/Fiter systems, regardless of how they are marketed).  However, as you will see in the coming paragraphs, ARC ultimately is an equally important part of the system performance equation, on par with room acoustics.  It is a unique must-have component, whether your room is acoustically poor or excellent.