I sit in a low-backed old turn of the century chair, because it's a Victorian living room. I had used a more comfortable, higher backed chair, but that screwed up the sound, as others are noting. This is a quandry, particularly if the music relaxes you into falling asleep as discussed in another thread (yeah, I sometimes fall asleep listening too). The most comfortable chair I ever sat in listening to music was one of those Backsaver zero-gravity recliners which my local dealer had for a while in his store, which had a wide headrest so it wasn't the greatest for serious listening but was heaven to sit back in and let the music wash over you.
Your Listening chair
How elaborate is your chair? I use a beach chair and use two throw pillows to reach the tweeter height.Very transparent, acoustically. Only problem is the back support just ends up little below my neck level.And does not provide head rest-which is painful for longer sessions. My question: How important not to have a head rest on your chair? I have experimented with a head rest and sound becomes somewhat non-transparent loosing its ambience. Without the head rest sound is more open and natural.