Abstract <p>Reducing noise in the cabin of propeller aircraft is an urgent problem of internal acoustics, since traditional sound-insulating structures are insufficiently effective in the low-frequency region. One promising method for solving it is to use resonance systems, with which it is possible to significantly increase the sound insulation of the fuselage structure of aircraft in this frequency range. The study determined the effect of resonance systems on the sound-insulating ability of flat and cylindrical panels without and with cross stiffening simulating the body bulkhead frame was experimentally determined, as well as the effectiveness of facing the passenger compartment with resonance systems with different compositions. Tests were carried out in sound chambers and on a full-scale bench, which is a real passenger plane. The tested structures were faced with elastoacoustic compensators of various types with resonance elements made of foil, micalent paper, and thermopolyurethane. It is shown that the efficiency of resonance systems can reach 10–20 dB or more.</p>