Most rooms don’t need acoustical treatment.

I set up my room using acoustical principals but without using specialized products. I don't have any glazed pictures in the room. The art on my walls are wood carvings and tapestries. It's relatively balanced. I've done this so many timesI feel I'm getting a 6th sense about getting good sound out of a room. What I've noticed is that old homes with thicker, stiffer walls do much better than the thin drywall in newer homes. Older, concrete-based acoustic ceilings are gold.
Is it the best case scenario? No. But it works well enough to fool me. Now, I've had better rooms to deal with but I do also enjoy looking at the room I listen in as well. It's part of the equation for me.

Most treatment, to me, looks ill. And, let's be honest, the sound/signal does not care if it's a specialized product or not. I imagine even the best treated rooms using the latest tech aren't a perfect exploitation of their potential.

@asvjerry 

It's 'sand them all'. 

Back in design school, I was in line in the shop to return some tools. A friend of mine walks up and asks the guy in front of me if he should sand just one of the pieces of wood for a project.
The guy responds by saying 'just sand them all'.
Then they both pause as a light flickers in their nerdy eyes before they burst out in laughter.

My name is Sandamal. It's a perfect phonetical pronunciation of my name. And once again, as it has so many times, my name has betrayed me.

I think it matters a lot. In 2017,  I reluctantly moved one piece of furniture and it made a big difference. I would say 100% difference. The system sounded twice as good. Moving my LP rack to the first reflection point on the left speaker was like finding the autofocus on a camera lens. And I simply rearranged the stuff that was already there.

That change alone made me chase optimum room configuration for 4 months.  I didn't use specialized products. This is how powerful a room can be.

I just never thought it could make that much difference all these 30 or so years...I would move the speakers around a bit and adjust a few things and if it sounded good, I thought that it was set. Didn't think to try a little harder. 

I know some smart people who think that this acoustic stuff is nonsense. Much of what we see influences our perceptions. 'I can see the stereo equipment...that I spent all this money on...so yeah, it sounds better...it looks expensive...it must sound good'. But you can't see sound so that's a little tougher.

A lot of people defer their other senses to sight. I see therefore I believe. 

Buy a good book on getting good sound out of a room. Try the principles. They will help you hear the room. But you won't change your room until you move. The room makes the most difference.
So it makes it tougher to appreciate.

People often hear only subtle improvements because they make changes WITHIN the room.
They don't have the option of moving rooms so easily. So that reinforces the feeling that acoustic treatments are silly. 

The room is an instrument..and a big player in the sound game. But changing/adding a few minor things and expecting a miracle is futile. But if you can reorient a few critical things, the things that matter most. It would seem like a small miracle occured. 

But people really aren't open to putting the rack on the side wall...or having zero equipment between the speakers. That sounds extreme.

I did this for a short while right before I moved. It was the best thing I ever did. Can't do it now in the current smaller house...but man, you guys (some of you) really have no clue...I mean NO CLUE what you're missing. You also have no clue what you're talking about (again some of you).

Try it. Please try something...before you go off 'dropping your knowledge' on us.