Unless you need to create added height (angular incidence to cause the ear to perceive the sound as higher)all main and surround speakers should be at a height that conveys a realistic sound and surround stage height.
This may also be impacted by the vertical dispersion charachteristics of a particular speaker.
The suggestion of "above the listener" positioning you mention was originally based on attempting to create a less direct and more diffuse surround soundfield.
As well the placement of the side surrounds further to the rear (as opposed to directly to the side) was also to create the angular firing incidence that would make the ear/brain "hear" a more rearward directionality.
With 7.1 this is no longer needed.
In well recorded multi-channel music, the sides and rear speakers "should" only be for sonic support of that ambiant information that you would hear while actually sitting in the venue.
Using and positioning the speakers should be based on the best position for them to have the best reproduction. When listening to music, that is generally NOT with high firing angles.
IMO
This may also be impacted by the vertical dispersion charachteristics of a particular speaker.
The suggestion of "above the listener" positioning you mention was originally based on attempting to create a less direct and more diffuse surround soundfield.
As well the placement of the side surrounds further to the rear (as opposed to directly to the side) was also to create the angular firing incidence that would make the ear/brain "hear" a more rearward directionality.
With 7.1 this is no longer needed.
In well recorded multi-channel music, the sides and rear speakers "should" only be for sonic support of that ambiant information that you would hear while actually sitting in the venue.
Using and positioning the speakers should be based on the best position for them to have the best reproduction. When listening to music, that is generally NOT with high firing angles.
IMO