Since Linkwitz has been held up as an audio authority, might look at the Danny Richie video fixing the Linkwitz Orion speaker (open baffle). The before measured response is pretty bad and Danny points out rookie design mistakes like enclosure edge diffraction problems and driver acoustic centers.
TLS Guy has a very nice room and presents pretty good measurements. From the pictures difficult to tell if there is any significant room treatment. Appears to be many hard, flat reflective surfaces. Regardless, appears TLS Guy is measurements tell everything believer, so his ears will hear perfect sound quality regardless. A claimed 60 year hobbyist does not equate to expertise superior to individuals with decades in the business of designing, building, and collecting awards.
There are no obvious room treatments, and certainly no ugly wall panels, but the room is treated.
1). The most important thing is that the room has optimal dimensions.
2). The room is rigid and there is treatment behind the walls and under the floor. The choice of lambs wool for the carpet was also deliberate.
3). The position of the main speakers that also reproduce the LFE signal and the lowest frequencies have carefully designed spaces around them. Also the actual design of the speakers, with their swept sides are a part of the whole plan.
4) All but the ceiling and surrounds are TL designs. These speakers are unique in their ability to give uniform bass coverage over the room. In addition only the ceiling speakers are crossed over. The right and left fronts are truly full range. The center rolls off only 12 db per octave from 44 Hz. The surrounds roll off 12 db per octave at 50 Hz. The rear backs are very close to full range., with an f3 of 30 Hz and 12 db roll off, so barely 6 db down at 20 Hz. There are no subs scattered about the place. Care has been taken to disturb time shifts to the absolute minimum. There is no gross trespass of separating fundamentals from harmonics, in time and space. BSC is controllable on all speakers except the ceiling. The surrounds just have two settings, but the others are continuously variable.
You have to remember these rooms are living spaces, and need to be comfortable. A totally integrated design like mine, manages to achieve this without making an architectural dogs dinner.
So this design is a totally integrated design without running roughshod over aesthetics.
I do carefully listen. I learned this from early from my mentors, especially John Wright. Once you have things acceptable then listen for three months before making changes. So yes, my speakers do often undergo a number of iterations, but less with more experience.
I did submit a design of mine to the audiophile sound off some years ago and it won first place.
I have had experienced engineers tell me this is the best room they have ever heard. Prior to Covid-19 many used this room and especially the room on Benedict Lake as there preferred room for mastering. This room sounds better as its design and construction could be optimized.
So, yes the room is treated, but that is not obvious as it is a total integrated design.
Lastly I would say the better speakers are, the less the room appears to affect them. A lot of this hanging strange structures is actually trying to reduce speaker shortcomings.
