ITU worst case listening position - how?

[Nils Peters <nils.peters@xxxxxxxxx>]

Hi,

I hope someone from this list can help out, the ITU people could not 
sufficiently answer my question.


The ITU-R BS.1116-1 recommendation "METHODS FOR THE SUBJECTIVE 
ASSESSMENT OF SMALL IMPAIRMENTS IN AUDIO SYSTEMS INCLUDING MULTICHANNEL 
SOUND SYSTEMS" (p.18, Figure 7) defines the typical 5 channel surround 
loudspeaker setup including the best (central) and worst case listening 
positions.

Here my question:

What are the underlying assumptions/calculations that make these 
specific listening positions to the "worst case listening positions" ?

The text on the same pages also defines the recommended listening area 
which has a radius of 0.7 m around the central position. I am also 
wondering where this number comes from.


thanks for any comment.


Nils