I would suggest staying away from ceiling speakers if at all possible. They will give you a fairly locatable and false surround image. Instead, try the following>
1. Move your front left and right speakers up even with the plane of your TV. This will improve their polar response toward the center which in turn will result in smoother and more natural sounding left to right transitions on movies and music.
2. Move your dipole/bipoles down to 5.5-6 feet and move them slightly forward of your seating position. You are trying to accomplish two things. On the left you want to get the surround speaker further from the rear wall (two meters is best). On the right (from your seating position) you want the surround speaker to "see" more wall both to the front and to the rear. Moves 1. and 2. should give you a more balanced sound from left to right.
3. Put absorptive material directly behind your sofa. Slap echoes can give you totally erroneous spacial cues, obscuring vocal articulation from the center channel.
Lastly read all three CEDIA seminar articles posted on this site. They will provide a wealth of information as to why these recommendations are being made. Let us know how much these simple changes increase your system's performance!
