Most rooms don’t need acoustical treatment.

I was always under that assumption until I heard the difference a good well place sound diffuser made to the sound stage and presentation. I had a demonstration done to me and an audiophile group in a private home. The person that did the demonstration had no diffuser in the beginning and every one thought that it sounded great. All of a sudden, he mentions, "you guys want to hear something?" and he adds the diffuser on the front wall as the music was playing. The difference was knight and day. The depth, with, definition and stereo imaging was transformed for the better in a huge way. The minute he removed it, the stage fell back to it's former small self. Could be the way he made the diffuser that created all the difference. Materiel, design ext.  I have some in my home but could not afford his asking price so I bought from a competitor. Because of that, I get just about 10% of the effect. 

Maybe i purchase abunch of foam bass traps off amazon for about 50 bucks and see what happens.  Not much to lose.  Anybody use these?

@coachpoconner

Millercarbon- What does “As soon as we move from the
hypothetical home of the scoundrel to the particular home of the individual then acoustic treatment can suddenly matter a lot.”

On what planet do you exist? Why was it important to include the word “scoundrel”? Are you trying to come off as some kind of “Audio Sage”

You hit the nail on the head with this one. MC does think he is an "Audio Sage". As a matter of fact he’s a blowhard know-it-all.He relishes putting people down with sarcasm. And, if you watch, almost every new thread he is one of the first responders. So full of it. He doesn’t have a life or really listen to music, he just spends all of his time posting here.

Helmholtz resonators aren't something you can just add to a room willy billy, they are very hard to get right even with proper measurements.

All rooms need acoustic treatment . Trick is not to over damp the room.  Even furniture and household objects scattered in a room is acoustic treatment