The high-frequency part of the sound wave spectrum generated by an initial impact of a liquid drop falling onto a quiescent liquid surface is considered. The pressure fluctuation distribution obtained by Guo and Ffowcs Williams [5] is employed. The influence of a noise produced by bubbles entrainment by drop is not taken into account. The analytic results show that the spectral density of an acoustic energy in a high-frequency range varies inversely proportionally to the squared frequency value and diminishes with the frequency increase approximately of 6 decibel per octave.