There is a reason why many speaker designers test their products in anechoic chambers. Doing so eliminates the effects of the vagaries encountered in rooms in which the speakers may be used. On the other hand, some designers try to make speakers that are "room friendly," IMHO an impossible objective. There are too many variables, with rooms of all shapes and sizes, containing reflective and absorbing surfaces, and furnishings of all kinds.
So what is an audiophile to do?
First, have a room that your significant other allows you to take over. Then treat the crap out of it! I have a 25X15x9.5’ room that I have treated with sound-absorbing panels, on walls, and ceiling. I am able to do this on three walls and the ceiling. The 4th wall is partially taken up by a brick fireplace, so no panels there. However, there are panels on both sides of the bricks. The floor is tile, covered in substantial part by a rug with a layer of padding beneath it.
The panels went up a bit at a time. Each time I added more, I could hear performance changes, always for the better.
Naturally, I kept adding more panels.
In my room, I can hear changes when about six of the 1-foot square panels I used are added. Less than that, I can’t discern much difference.
It makes perfect sense. The panels make the room less reflective and quieter. The quiet is measurable with a good sound pressure meter. More quiet allows audibly greater detail and improved dynamics.
For those with the funds, I recommend that you have your room treated professionally. But it can also be a DIY project for those so inclined and capable.
My current setup includes Tekton Double Impact speakers and a pair of their self-powered 4-10 woofers, a Muzishare R100 805 integrated Single-ended amp (into which I’ve poured a lot of $$$ for tube upgrades and performed an internal output capacitor bypass - a potential subject for another discussion), the Audiolab 9000 CD transport, and the Gustard R26 (ladder) DAC. The transport and DAC are powered by a battery power supply (a nice improvement that can be had for far less than expensive power cables and filters). The speaker cables are the extraordinary Wireworld Eclipse 10. I use two pair since my speakers are bi-ampable. (As a major speaker cable skeptic, I have been amazed by the changes wrought by these cables. I run 20-foot lengths.) Sitting idle are my upgraded Parasound JC2 preamp and A21 amp, and a speaker system comprised of rare, classic Altec drivers in expensive Japanese-built cabinets, with German-built horns atop for frequencies above 400 HZ. (All else being equal, I am spoiled by sensitive speakers).