Question frequently arises : how large should you scan around listener head position ? Move in all directions, even height, but avoid to be too near of a reflecting surface, ie stay a bit higher than the back of the chair.
I would scan within about +-15° off axis, that is nearly 50cm in all directions for a loudspeaker at 2m and 100cm at 4m.
Il faut se rappeler que pour un système audio domestique, la méthode MMM permet de lisser certaines réflexions et pas de moyenner pour différents utilisateurs.