Anti-noise generator for extinguishing low-frequency, periodical noise field by means of sirens

摘要

The sirens have a resonator in the air inlet and/or the air outlet. At least two sirens (11), with a pre- and after-resonator (12,13), have a first siren and its corresponding resonators matched to the basic frequency of the sound field and a second siren and its corresponding resonators matched to double the basic frequency of the sound field. At least two sirens each with a pre-resonator and a common after-resonator involve one siren being operated with excess pressure and a second siren with vacuum. The effective resonator length is variable. The resonator inner wall has a high compressibility and/or a coating (14) with air-permeable material.