I wonder if both speaker placement and room treatment can be overrated. To be more exact, if the sound of gear is highly room dependent, doesn't it follow that the efficacy of speaker placement and room treatment is also room dependent? I pose this because I've had both experiences. My room previous to the one I have now was relatively small, 12w x 18l x 9h. For a time, I had a Classe processor and amp powering a pair of B&W 802Ds. The 802s are supposedly fairly forgiving of room size, but, in my room, the soundstage and the sound both were congested, with the instruments all piled on top of each other in a small space between the speakers. A friend of mine happened to buy a collection of random bass traps and panels, so we stacked two corner bass traps from floor to ceiling in the corners behind the speakers, a 2" thick panel at each of the first reflection points, and three of the 2" panels on the wall at the back of the room. This was done without taking any measurements and was about as unscientific as a couple of bumbling would-be audiophiles could wish. The result was nothing short of astonishing. The soundstage opened up, each instrument (in smaller ensemble jazz, classical, blues, and some rock and Indie-type recordings) was clearly placed with space between each, the sound opened up, became clearer, smoother, just altogether more listenable. It made me a believer in room treatment. I later sold my 802s and switched to stand mount Dynaudio Heritage Specials. I didn't try these without my slapdash treatment, but, with it, they imaged even better than the 802s and were more pleasant to listen to, in part, I expect, because they better suited the room's size.
Jump ahead to my current room, which is somewhat larger (15w x 30l x 10h), full of hard surfaces, asymmetrical planes, and a big tv too close to one of the first reflection points. I started in the room with the same Classe pre-pro and amp and Dynaudio Heritage Specials. Surprisingly, the sound was better than it was in my old treated (however unprofessionally) room. And I don't mean a little bit better, but better enough that it seemed like I had a new pair of speakers. The soundstage was larger, deeper, better defined, and the speakers disappeared to the point of their presence in the room being almost comical in that they seemed to have absolutely nothing to do with the music. I'm guessing these improvements were down to the room's size, that the distance of the walls from the speakers reduced the amount of room interaction. Since then, I've completely revised my system. I swapped my Dynaudios for a pair of Spatial Audio X5s and my Classe pre and 300 wpc ss amp for a Don Sachs tube 30 wpc Valhalla. Initially, I still had my Class when I first got my X5s. I wouldn't say the tone of the X5s was better than that of the Dynaudios, but the bass was bigger, as was the scale of both the sound and soundstage. Again, all this glorious sound is taking place in an entirely untreated room, with no particular effort to locate the speakers which, regardless, due to some oddities of the room's construction, had to be placed asymmetrically. Finally, I got rid of the Classe and replaced it with the Valhalla. With the addition of the Valhalla, everything about the sound improved, perhaps not as dramatically as when I first added the treatment to my old room, but significantly and in many of the same ways. The soundstage became wider, deeper, higher, more 3d, with greater separation and clarity. The sound itself was more resolved, with more micro-detail, while the tone was warmer and richer, again, just more pleasant to listen to. And that's saying something, as the Heritage Specials are remarkable speakers, with a beautiful midrange and effortless highs that can be listened to at high volumes without feeling attacked, though I suppose that might depend on the music.
So, my question is, as I've got so many of the qualities most systems and audiophiles reputedly aspire to - a wide, high, and deeply layered soundstage, great specificity of instrument placement and separation, a (by my lights) sound that is highly resolved and full of detail, while at the same time warm, mellifluous, and just really good to listen to - would adding treatment really be helpful? I suppose true acolytes of treatment would argue it would get even better with treatment, that each of those qualities would be, however slightly or greatly, enhanced. Obviously, I can't say without trying it, but I wonder. I know of a truly world class system in a large very open room with vaulted ceilings and an essentially entire wall of glass behind the speakers, entirely untreated and asymmetrical, and he swears (as he builds high-end amps for a living, I have no room to doubt him) his system sounds as world class as the gear would suggest. Again, it just makes me wonder whether treatment and placement are always of such paramount or even particular importance. My room is far from perfect, and the sound is the best I've ever owned and in the ballpark of the best I've heard in well-treated showrooms. I readily admit, my frame of reference is limited, but I've owned and heard some decent gear. I'd be curious to know if anyone else has had a similar experience, that the sound in their room seems uncompromised by the lack of treatment or overly fussy speaker placement. To reiterate, I'm not saying placement and treatment can't be helpful, even very helpful. Clearly, they've been helpful in the OP's room. I just am not convinced either is always as necessary or important as many suggest.