Doctrine actuelle d'insonorisation des cabines d'avion

After defining the criterion of acoustic comfort in aircraft cabins, the author shows the importance of reducing therein the noise of propulsion, which is ascribed to the directional characteristics of the radiated sound. It appears possible with a fuselage not comprising plane surfaces to cut down the transmission of the low frequencies.

Light materials are suitable for this purpose. Knowledge of their coefficients of transmission and absorption permits a calculation of the likely reductions of noise level and these predictions are tested against practical examples.