Conducting an interesting placement experiment for the two rears in a 7.1 setup. My room will not allow the 7.1 official layout as per Dolby / THX recommendations. Mainly due to having the listening position (sofa) pretty much on the wall opposite the TV but it's further complicated by the sofa being alcoved. Stairwell on left of sofa, living room door from hall in projection into the room on right of sofa. After much study I have gone with the rear atmos pair on the rear wall up at ceiling height firing straight down (behind listening position - just). The front Atmos pair are pretty much midway between the rear pair and the front left and right as per the Dolby recommended layout for 7.1.4. I have them angled to fire at the middle of the sofa. Typically there will either be one or two people on the sofa. Where I get controversial is with the thread title speakers. I have positioned them between listening position 1 and 2, equidistant from the middle of the sofa. This is opposed to outside the listening positions as per the Dolby layout. I am forced into this because of the alcove. My thinking is that overhead sweeps or left/right, front/back pans should still be preserved as curves on the relevant axis with the only impact on the sound field being that sound objects which are meant to travel to these rear two speakers will end up behind and between the listening positions as opposed to behind and outside. I think this will work ok. I'm just awaiting imminent arrival of a new sub and then I will get to testing this revised 7.1 layout. The ceiling speakers will have to wait a while before I get them going.