Bang & Olufsen BeoPlay A9 User Manual page 5

Position switch:
When you place your BeoPlay A9, you must also set the position
switch correctly. The position switch influences the sound field
around the BeoPlay A9.
When you mount BeoPlay A9 on the wall bracket or place it closer
than 1 meter from a wall, you must set the position switch to
position WALL.
When you place BeoPlay A9 in a corner closer than 1 meter from
the walls, you must set the position switch to CORNER.
When BeoPlay A9 is placed more than 1 meter from walls, you
must set the position switch to FREE.
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