As I went down the thread, I was going to ask why no one is bothering to mention the room, but Snarfie23 saved the day, and with empirical measurements no less.
Measuring isn’t everything, of course. But I can offer you my personal, anecdotal experience that confirms Snarfie23’s post, notwithstanding MC’s clamorous protestations to the contrary.
For 41 years, my system suffered from brightness and harshness in a 1,200 sq ft space in a 2,000 sq ft NYC loft.
Then, I moved into a townhouse that I renovated and restored. My office and (smaller, 550 sq ft) listening room is in the attic. I did not cover the 17" of rock wool insulation with sheetrock. I instead simply put fire-resistant burlap over it.
The problem went away.
As I slowly populated my bookshelves with my library, it came back, only a little.
The cliche is true: the room is 50% of your system. Maybe more.
You are welcome to try it and see if it works for you.
Full disclosure: I am neutral on cables.