Treating the ceiling and floor, who else has had great results?

@erik_squires   -  I agreed with you that the area between and behind being oversights. 

I have a small 12'x12', 10' ceiling room.  And it has been a b*tch to treat.  I'm intending to build a proper dedicated room with better dimensions, but that is at least a year off.

I did all the 1st reflection points, back wall, bass traps in corners (floor to ceiling), corner /ceiling traps, carpet in front all the way to the listening chair, etc.  It wasn't until I bought some big pillows, used for dog beds, behind the speakers and partly up the front wall until I was able to get the boomy , smeared bass somewhat under control.  I know it is knocking down the reflections bouncing around the room, but it was also knocking down the bass coming out rear port on my Totem Wind speakers.

I still need to play with doing something about the equipment rack between the speakers.

As for the ceiling, I tried using horizontal bass trap panels hanging from the ceiling at it's 1st reflection point.  It was "ok", but it seemed to kill any airiness in the sound.  I'm suspecting that I've reached a point where I've over damped the room.  so, I'm building a set of diffuser panels to replace some of the absorption ones, and will try those on the ceiling.  Going to interesting to see what happens.

@jeffbij 

Been there too, over damping the room. Biggest fix was diffusers at the two first reflection points on sidewalls. Also using strictly diffusers on ceiling. You can see multiple pics on my house of stereo system.

@baylinor   How are those white PVC diffusers working out.  I've been a litte wary of them because being PVC they should be highly reflective and because there is not much of a difference between the high and low points.  (Unlike most quadratic diffusers I've seen.)

They perform real well if you use them over large areas. By example, I have 28 sq ft on ceiling, 8 sq ft on each back sidewalls and 15 sq ft on back wall. Of course the 6" deep wooden diffusers I have at both first reflection points diffuse in another league, but for a different price too 😊

My floor is wall to wall carpet with padding underneath, and I put 18” triangle bass absorbers in the front corners, but putting anything on the ceiling is not wife approved! Although I was allowed to put 6, 2’X4’ absorbers on the walls.

All in all I’m pretty happy with the sound in my room.