Don't we all already know Dr. Toole recommend DRC/Auto EQ be applied to the low frequency range below the specific room's "transition/Schroeder" frequency? I don't think he has ever said anything about the validity of doing it above the transition frequency, but he obviously suggested that doing so may do more harm than good and there's no need to do it if the speakers have good off-axis response. As you know, there are all kinds of self proclaim experts who, in my opinion should just quote/link the experts instead of trying to explain things away that they don't really understand enough.
One concern that I do know of is that, measurements taken above the Schroeder frequency may not be reliable, but it obviously depends on the software/hardware. If you talk to the Dr. Johansson of Dirac Live, Dr. Schuck of Anthem and Dr. Chriskakis of Audyssey Lab., you are going to get slight variations of their interpretations of the issues cited by various experts.
Anthem did offer a little bit of explanations:
ARC Auto EQ: Today the Audioholics had a chat with Anthem's Nick Platsis to get the inside scoop on Anthem Room Correction (ARC). Click to learn all about ARC the wonders of great EQ.
www.audioholics.com
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Nick Platsis: It is reliable up to 5 kHz. After that it starts becoming too directional with increasing frequency. Maximum correction range for MRX receivers is 5 kHz. This is the normally recommended setting, and the default, in all versions of ARC and is user adjustable down to 200 Hz. In AVM/D it can be set as high as 20 kHz, but effectiveness of correction at these upper frequencies often depends on whether the tweeters (and mic) are at ear level. A listening test is the best way to find out."
In case you may not know, Audioholics did interview the Doctors of Audyssey and Dirac Live as well:
Room EQ: Today the Audioholics have a chat with Mathias Johansson to get the inside scoop on Dirac's room correction products. Click to learn all about Dirac Live and Unison.
www.audioholics.com
The Audioholics interview Chris Kyriakakis in order to learn the ins and outs of Audyssey's MultEQ room correction / auto-calibration system. Bass management, calibration, EQ and more.
www.audioholics.com
With the introduction of the Editor App, all 3 of the major players in the AVR field provide the means to limit the affected frequency range.
I really don't see a short answer to your question but it is there if you spend time reading some of Dr. Toole's articles.
Below are what I would like to quote/link:
Solving bass problems in small rooms have historically been done with low frequency absorption (ie. bass traps). This article discusses an alternative/complimentary solution using multi-sub and SFM.
www.audioholics.com
Or if you prefer to just read part of his conclusion below (no detailed explanation though..)
"Whatever solution(s) you choose, it is likely that some bass equalization will improve things. Just don't automatically extend the equalization above a few hundred Hz, because that is where the loudspeaker itself takes over and if you have good loudspeakers you might risk making them worse.
Make your choices, it is a free world."
Another great one to read:
PDF | The steady-state amplitude response measured at listening locations in a room is a widely accepted indicator of sound quality in sound... | Find, read and cite all the research you need on ResearchGate
www.researchgate.net