Rear speaker placement dilema (pic inside)

I posted this in the speaker section, but only got replies from one guy. While his advise seemed good, I want others advise as well on my situation. Hopefully this forum will help me some more. I need to make a final decision this week, as I plan to install the speakers next weekend.


I have in-wall speakers for everything except the rears in my living room/ makeshift HT. One of my current rear speakers has given up the ghost, so it looks like it is time to follow suit and put some in-walls in this location as well. I have done a good deal of research, and I think I have decided on speakercraft AIM8's. I was so impressed by the AIM Cinema One’s I recently put in the front, I am confident in sticking with speakercraft for the rears as well. My only dilemma (if it even is one) is that I want to put these in the upper back wall of my room. There really is no vertical wall for the first 9’ since it is open to the room behind it, but the top 3’ of the vaulted part of the ceiling does have a vertical wall with ample clearance for a deeper in-wall speaker like the AIM8 is. I know this speaker was designed as an in-ceiling speaker, but would there be any disadvantages to placing it vertically in a wall facing forward as opposed to horizontally facing down?


Here is the current setup. I would like to put the speakers on the vertical wall (blue location). But if that is a problem and the speakers would work best pointed down, I can put them in the top of the living room ceiling near the back (green position), or I can put them in the ceiling of the adjacent room slightly behind the living room technically, but in the same area (red position). Also, keep in mind, these are aimable, so I can point them in some extent towards the primary listening position in any of the proposed configurations..


So would putting the speakers on a vertical wall be problematic?




It may also be worth noting that even though I have side speakers as shown in the picture above, I have decided not to use those since the primary seating position is a few feet behind those speakers, so they are not ideal for side surrounds. And the wife has dictated that rearranging the furniture is not an option, therefore changing the seating arrangement such that the side surrounds would be ideal is sadly out of the question..


So the rear speakers that this thread is about are going to be the only rear speakers in the room (17.5' x 17.5'). I am using a 7.1 configuration, but it is 5.1 + heights.


To me, it seems the benefits of it being in the blue position seems like it will keep the sound in the room better, and also would allow for people in the side walls seating positions to hear the surrounds better. The pic below shows the front of the room.




As you can see, there is a couch along the right side wall, and a chair on the left side wall (you can only see the right side of the armrest in that pic). I want these positions to be able to hear the surround effects too. I know they will be a bit skewed towards the side they are located on, but there is no avoiding that anyway.


Thanks for any help or input everyone!