Here, I disagree with you my friend.
When people say "Reference" isn't it fair to say they are typically talking about the 20+ year old "Reference" standard as defined by THX? 85dB at MLP with 20dB reserved for dynamic headroom.
Clearly a standard reference listening volume requires different amounts of capability based on room size and MLP distance.
http://www.thx.com/consumer/home-en...ter/thx-certification-performance-categories/
The different ratings, select, ultra, ultra 2 speak to capability of both speaker design and power requirement as related to size of room and distance to main listening position --- it helps signify to the consumer what is required to drive the equipment to the established THX defined Reference level of 85dB with headroom for 20dB peaks.
A smaller, less capable, less sensitive speaker may be able to hit reference level audio in smaller room with a close main listening position. Thus a select cert is appropriate where that same system could not achieve reference in a large room with a more distant MLP. That room may require a THX ULTRA II cert within their hierarchy. That is what the THX labels mean. (For example In some cases a specific quantity of subwoofers was needed on a particularly labeled subwoofer to achieve the THX label - a THX rated Crystal Accoustic subwoofer was one such instance I crossed paths with --- the documentation stated it required four of the 12" subs to achieve the THX Ultra II branding.
http://www.avsforum.com/forum/113-s...hs.html#/forumsite/3207/topics/1408856?page=1 )
The THX cert labels are just one way of trying to inform a consumer of what level (quantity) of matching gear is likely needed to try to achieve a standardized SPL listening level for cinema.
Is it fool proof? No. Is it universal no. Is it a money/branding/marketing grab? Yes.
Has there been a better, more widely accepted proposal in the last two decades from another vendor? Not that I'm aware of.
You know all this
My hope in my posts on this is to inform some of the "reference is whatever my preference" type posters in this thread, as well as the wild SPL confusion that various posters have dumped into this thread. Reference has been defined for decades. It may not be meet all peoples' preferences (too loud, too soft, too generic, not addressing subsonic frequency, or hearing curves, or any number of personal insults to ones personal audio preferences and subjectivity) ------ and yes it is not used universally by studios in mixing.
But the lack of universal following of the standard doesn't change what the standard is.