I am looking for some advice regarding speaker placement. I currently have a 5.1 system that I want to set up in the 27' x 11' main area of my basement that has two other rooms off to the left-hand side about halfway through the room, i.e., it's not a perfect rectangle. Because of the other rooms, I will not be able to put the surround speakers exactly at 90 degrees but can put them at 110 degrees. I was planning on having the main seating area about 10-12' back from a 120" diagonal screen.
My questions are these:
1. Based on the 27' room and thus the large area behind the main viewing spot, is it worthwhile to get 2 more speakers to put in for true rear speakers?
2. What should the height of the speakers be? I know the center speaker needs to be either below or above the screen, but I've seen conflicting opinions on whether the other speakers should be at ear height or above ear height.
3. Would front height speakers be a better option than the rear speakers?
4. How difficult will it be to match the 2 extra speakers, if warranted, to the current speakers?
Any advice would be appreciated. Thanks.