Most rooms don’t need acoustical treatment.

+1 Millercarbon (best point)

Yes, and no. Past a certain point, the nuance any given system may behold can be more achievable with focused attention on surfaces and corners where treatment could be of considerable benefit. 

All rooms need treatment asap.

Diffusers?  What about 1d (lateral) vs 2d (scatter).

wouldnt 1 d be best if ceilings are flat?  Why bounce scattered waves off a ceiling???

Not only ALL rooms need treatment. but audio experience could be 75 % acoustical, 25 % basic good electronic design...

This % is variable, but NEVER in favor of the electronic design like 49% acoustical, 51 % electronic design...

This is pure science....

The sound you listen to come from the room /speakers, NEVER from the speakers alone in a small room especially...


It takes audio magazine market to make us believe that  "upgrading"  a10,000 dollars amplifier to a 100,000 dollars one, will be the key to audiophile experience.... Helmholtz has known much about sound perception one century ago than consumers magazine now...

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.