I looked at the Dolby site that shows the positioning of the 4 back speakers. They show the side speakers at 90 to 110 degrees (directly at the side to back 20 deg). They show the rears at 30 to 45 degrees from straight back. It seems that several people advise placing the sides at 90 deg or slightly forward. I plan to listen with them in various positions, but any advice or experience would be appreciated.