How high the rears?

I like it higher on the wall so as to not get directional sound that is easily placed by ear. But this is one of those topics where you will get a few opinions.
To me I should not hear the output from the actual speaker, I want to hear it breathing in the room but not able to pinpoint its position, that happens for me when its close to my ear level.
You are 4ft away and I think this may happen for you aswell but its just a guess.

I believe 6 feet off the floor is about right. You're right, voice matching for rears is not that important. Even with DD and DTS rears still mainly serve as sound effects speakers.

Ideally, the rears are placed further apart than the main LR speakers. I've got my mains about 8 feet apart in a 15X13 room, with the rears in the back corners (so 14' apart), about 6 feet up, angled in 45 degrees. With the sofa on the rear wall, that keeps the rears well away from our ears, allowing for good ambient sound.

Sorry John but Toni Grimmani and Lucas Sound disagree!

The rears should always be placed close to the ceiling and never at the ear level. Rears are supposed to be diffusive even in a direct radiating system. The idea of surround sound is to mimic what you hear in reality, as you move further and further away from a sound source you loose exact placement and instead hear the sound as emanating from a destination location. Most surround sound effects are trying to duplicate spacial cues to mimic the reverb times of large spaces to pull you into the movie, or to recreate pans from side to side or front to back.

If you can pin point where the sound is coming from you are defeating the concept. Direction not location is what we are aiming for. In fact most professional theater designer still prefer di-poles radiators for the side locations whenever possible.

I guess you learn something every day.

Chad,

I just measured the distance from our ears to the rear wall, and it's about 80".

db