To enhance the illusive power of the localization setup, it is recommended to install sham loudspeakers at 10° from one another around the listener.
At random, A§E plays the sound through the real loudspeakers with a level difference of Δ I.
The listener is asked to point the most likely source of this sound. This is one of the 13 loudspeakers numbered from -6 to plus 6.
For the test to be valid, it is important that the listener faces the sham loudspeaker in front and does not move the head.