METHOD FOR SETTING THE FREQUENCY CHARACTERISTICS OF SOUND-ABSORBING SYSTEMS AND MATERIALS Russian patent published in 2023 - IPC G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention relates to the fields of building acoustics and transport engineering. Substance of the invention consists in determining the spectrum of the affecting noise and identifying the dominant spectral components therein, followed by setting the natural frequencies of the Helmholtz resonators to said components by selecting the sizes of the resonator determining the value of the natural frequency; and significantly increasing the mass of the medium oscillating in the neck in order to reset the natural frequency of the resonator to the low-frequency noise and infrasound region, wherefor the neck is filled with a different medium, e.g., a viscous liquid or gel, while preserving the gaseous medium in the cavity of the resonator, and if multiple dominant discrete components are identified in the spectrum, including those with a frequency differing by a decade or more, a resonator with a high mass of the medium in the neck is used at infrasound and low sound frequencies, and a resonator containing a gas medium in the entire volume thereof is used at high frequencies, wherein two insulating layers, an internal layer and external layer, made of, e.g., a gas and moisture impermeable dynamically pliable film, are formed to retain the different medium in the neck of the resonator, so that the internal film layer separates the throat from the cavity, and the external film layer separates the neck of the resonator from the external environment. The Helmholtz resonator implemented with a high mass of a medium in the neck is also applied when creating a sound-absorbing material intended to suppress low-frequency noise, made in the form of a perforated panel mounted with a gap on the wall of a room, wherefor the holes in the panel are filled with another medium, e.g., a viscous liquid.

EFFECT: significant expansion of the boundaries of the range of operating noise-suppression frequencies into the low-frequency region, up to the infrasound range, without increasing the dimensions of the Helmholtz resonator.

2 cl, 8 dwg, 1 tbl