Interference suppressors, they work on the principle of extinguishing sound waves of the same frequency, but shifted in phase. For this purpose, the gas flows through parallel paths of different lengths. However, such an attenuator is only effective for a specific wave frequency, unless an arrangement with different branches is constructed, selected for a number of fundamental frequencies. Since the effectiveness of the interference suppressor depends on the rotational speed of the crankshaft, its use in traction motors is small.