The comment about a vocalist singing to you in your listening room is also interesting. What if the vocalist is at some acoustic venue such as a night club, a church, or up on stage in a hall somewhere? Do you still want a presentation telling you that he or she is singing to you in your room and not that you are there listening to him or her in the venue where the recording was made? If that is indeed the case, such a goal would likely affect how you treat your listening room. If you prioritize the sound of your room over the ambiance captured on the recording, you would want your room acoustics to overshadow the setting information embedded on the recording. In other words, you would not want your room to disappear, but instead to be clearly audible and to provide the backdrop acoustic for the singer.
Some of the room treatments I tried did indeed move the sound in this general direction. They absorbed much of the subtle, ambient information on the recording and did give me the impression that vocalists were very present in my room. They popped in front of me. It was a very high contrast type of sound with black backgrounds and that solo singer was right there at my fireplace singing for me.