The home theater working group of Japan Audio Society investigated the actual situation of 5.1 surround speaker placement at home theater. Also, they executed the listening test about listener's impression in various speaker placement
They have putted suggestion in order about 5.1 surround speaker placement at home theater. The report has described about tolerance level of difference between the REC ITU-R BS.775-2 and the actual speaker placement at home theater.
1. Angle of rear speakers
100-135 degrees
2. Up and down angle of center speaker
Best choice : L-C-R speakers are same floor.
If it's impossible , center speaker is max-20 degrees compare with L/R speakers.
3. In wall speakers
When speakers are placed at high position , you should place limit 16.7 degrees higher.
4. Speakers distance
Rear speakers should be placed less than +/- 10% compare with the distance of center speaker and listening
position.
