I would try any angle. Even pointing slightly out towards walls. As well as the other ideas here. Maybe need to see fronts too. Are u 5.1 or 7.1? In small rooms and setee close to wall u may need to try unusual positions and levels. You may need some traps too. Can u describe what the problem is too?
All this ONLY my opinion. Others may help too.
ps Is yr room 4m@5m? The settee against the 5m wall?
And we assume yr setup is good from amp?
Yamaha V2065. MS Mezzo 5.1 Panasonic 42. Sony BD. Garrard 86SB. WD Live TV. SkyHD.