DEVICE FOR ACTIVE DAMPING OF ACOUSTIC NOISE IN VENTILATION SYSTEMS Russian patent published in 2019 - IPC G10K11/178 

FIELD: acoustics.

SUBSTANCE: invention relates to means of protection against acoustic noise caused by operating ventilation systems in residential premises and in mobile objects. Device for active suppression of acoustic noise in ventilation systems, comprising a loudspeaker placed in a sealed housing, the emitting surface of which is located flush in the hole of the wall of the ventilation duct perpendicular to its axis, a pressure receiver located inside the ventilation duct near the radiating surface of the loudspeaker, electrically connected by a feedback circuit comprising series-connected preamplifier with electrically controlled transmission coefficient, compensator and inverting power amplifier, connected to loudspeaker, is equipped with second loudspeaker, placed in sealed housing, phase shifter, an additional power amplifier, wherein the second loudspeaker is located along the axis of the ventilation duct near the first loudspeaker, the emitting surface of which is flush with the wall of the ventilation duct perpendicular to its axis, input of phase shifter is electrically connected to output of compensator of feedback circuit of first loudspeaker, and output of phase shifter is connected in series to additional power amplifier and second loudspeaker, wherein distance between axes of loudspeakers in housing is much less than wavelength at upper boundary frequency of suppressed acoustic noise.

EFFECT: higher efficiency of noise suppression in ventilation systems due to reduced intensity of sound reflected back into channel and reduction of amplitude of standing waves between noise source and damping device.

1 cl, 1 dwg