Don't worry, Thierry, this is not how you think it is.
As you may know, all our samples are recorded in stereo, so they won't sit all "on the same place". There is a simple mathematical relation between the original width of a recorded signal in the SilentStage, and the witdh that the same signal has to have on a given stage with a give microphone-distcance. This is one of the already mentioned "less self explaining parameters" the MIR takes care for in the background.
So the left and right channel of an ensemble will be sent to the appropriate IR-position on any given stage (... actually it is more than just L/R, as any signal inside the MIR is processed in a threedimensional multichannel format, be it the dry instrument or an IR).
Of course it would be more obvious to have 14 small manikins sitting around on the virtual stage, but my idea was to keep the place as tidy as possible, visually [;)]