Thanks for that. I've noticed a lot of audiophiles who use extensive room treatments often leave the ceiling lightly treated or not treated at all. Some of them say they don't like it with too much absorption on the ceiling. Others might just be reticent to hang things on their ceiling. Do you focus on first reflection points when using ceiling treatments?
In regard to my post, while listening to headphones I wouldn't expect the ceiling absorbers to do much unless the headphones were very leaky and projected considerably more sound power away from my ears than towards them.