A theoretical model of acoustical wave (AW) generation by the area of low-thre-shold collective optical discharge (LCOD) is developed. The role of collective processes on LCOD acoustical spectrum formation both in sound (f ~102ё104Hz) and in hypersound (f ~105ё106 Hz) bands is pointed out. Direct diagnostics of LCOD dynamics and structure is shown to be feasible on the basis of spectral processing of sound band AW, received at considerable distances.