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

I treated my ceiling like I did my side walls for a high end 2 channel system in 4000 cubic feet space. The floor is carpeted. Lastly, the speakers are pulled out from the front wall with scatter plates behind them. Bass absorbers are inserted in the front corners. Locations for the admixture of absorption and reflection panels were determined based on 1st and 2nd reflections. The sound detail is magnificent, because the structural boundaries have disappeared — especially for depth of the sound stage. I found that strong equipment is made better by sound treatment of the listening space.

I have not specifically treated the ceiling, and think that would be a tough to sell with my chief decorator/LOML. However, there’s a textured ceiling, and two ceiling fan structures that may help with some diffraction....perhaps I could suggest a couple of well designed decorative medallions around them.

The floor was easy, with thick wall to wall carpet. The suspended floor underneath...not so helpful, but I bet I could get away with a few extra lolly posts in the crawl space below.

It's not ceiling/floor, but the large fireplace structure on the wall behind the speakers seems to offer some diffraction help. I’ve been bugging her about installing some book cases to further enhance that effect. We shall see!

I have 3 24x48x6 bass traps on the ceiling above my listening position. I also plan to hang 2 diffusion panels above my speakers. 

I use 4 (2ea side)Vicoustics Wavewood panels at 1st reflection point on 8’ ceiling. Very nice improvement.  Got rid of the drywall glare and opened things up. I like the look too

"No, a rug won’t help your room's reverb problem"

https://darko.audio/2025/02/no-a-rug-wont-help-your-rooms-reverb-problem/