Abstract: In the present paper the authors, based on their previous extended theory for nonlinear interaction of finite amplitude random sound waves （noise） and using the procedure of extraction of the regular sound from the signal-noise mixed sound, have derived the formulas for the suppression of the weak regular sound （simple harmonic sound） and the growth of its sideband components under the action of an intense random noise. This expression indicates that the suppression of the regular sound follows an exponential law, which is obviously different from that obtained under the interaction between two regular sound （simple harmonic waves）. An experiment was carried out in a long progressive wave tube with air to observe these phenomena. The experimental results show satisfactory agreement with the theoretical prediction.