If you have a nice system why do you really need room treatments?

 The problem is that homes are built with the worst possible acoustics. Walls and ceiling/floor all parallel to each other causing standing waves and their harmonics - all bad. That is the cause, breaking up those resonances is the only solution.

As this is allegedly a settled topic I will wade in only briefly:

- audio truism #1: the room is half your system.

- when my wife and I renovated our 1865 4.5 story brick townhouse based on a Calvert Vaux #5 design from his Villas and Cottages, I turned the 390 sq ft .5 story gable-ceilinged (no right angles) attic into my dedicated listening room. I did not cover the 5”-13” of rock wool insulation in the walls and ceilings with sheet rock. I instead covered it with fire resistant burlap. So: no acoustic panels: the entire ceiling and wall is an acoustic panel. Moroccan rugs cover the floor. The room is semi-anechoic: people immediately hear the difference in the sound quality of the room as they climb the stairs and enter the room.

See

theaudioatticvinylsundays.com

My room has catheral ceiling with a balcony. My system sound great to me.If having acoustically treated room would make my system sound like ,listening with headphones. That's interesting to me .I haven't used headphones in about 50 years.Using them would have killed my hearing.As we get older pur hearing disintegrates. I grew up in NYC with loud traffic,loud subways,seating up close to the stage and getting my ears blown out.Listing to my stereo loud.If i did use headphones for those 50 years now,I would certainly be deaf and not having the pleasure of listening to my music.If you use headphones while listening to music,Beware.

I'm not the smartest chip on the block and tend to be very slow at learning things but this thread has really been enlightening.  Fortunately I have a really nice wool rug and that's very helpful if I could only put it on the ceiling.  Maybe I need one of these diffusers although I may have to get a lot of them to be something meaningful since one or two probably don't do much.  All I read about acoustical measurements involved dedicated rooms that don't have furniture and that's not very helpful I like to see rooms that have lots of furniture stuff going on and then hear about decisions made to do some sound panels

There are so many really smart people contributing on this website. I was able to create this lovely comment through dictation and only touching the screen a couple times. You learn to speak more clearly and consider more carefully what you're saying when you dictate because if you screw up it's a bitch to edit

I’ve been in audio for 60 years, and haven’t corrected a room yet.