Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
Surrounds can be mounted up high, but I wouldn't install mains there. I'd prefer the mains to be around the same height as the screen.
Acoustically, boundary loading is a potential issue but the ceiling is a boundary just like the floor is. So boundary conditions would be similar when close to the ceiling as they are when close to the floor.
The issue to me is more one of maintaining the illusion of reality. We don't expect things to look like they're in front of us but sound like they're above us. That makes the sight and sound not match. Again, this isn't so much the case with surrounds as it is with mains. Surrounds are usually placed above the listeners and the soundtrack associated is designed for this position.