I will say that I've personally noticed that popcorn ceilings - once called acoustic ceilings - seem to work in preventing the kind of echo chamber you get with a flat ceiling. I would definitely vote to keep it based on my personal observations.
Popcorn Ceiling vs Smooth
I am in the process of remodeling/updating a home we just bought. My wife is having the popcorn ceiling removed in the whole house. In, what is to be my dedicated 2 channel listening room, I have the option to leave the popcorn ceiling or have it smoothed out. The room is 14x17 with 8.5 ft foot ceiling. Does anyone have experience or recommendations on which way to go? I have done a search and cannot find much on this topic. Thanks