US 12,462,783 B2
Active noise cancellation system for a helmet
Bent Even Fossum Fladmark, Trondheim (NO); Ronny Fagervik Larsen, Trondheim (NO); Dag Axel Aarset Loe, Trondheim (NO); and Sigmund Andreas Birkeland, Trondheim (NO)
Assigned to BPONTHS AS, Oslo (NO)
Appl. No. 17/290,765
Filed by DAAL Noise Control Systems AS, Trondheim (NO)
PCT Filed Nov. 6, 2019, PCT No. PCT/EP2019/080430
§ 371(c)(1), (2) Date May 2, 2021,
PCT Pub. No. WO2020/094733, PCT Pub. Date May 14, 2020.
Claims priority of application No. 1818094 (GB), filed on Nov. 6, 2018.
Prior Publication US 2022/0000206 A1, Jan. 6, 2022
Int. Cl. G10K 11/178 (2006.01); H04R 1/10 (2006.01)
CPC G10K 11/178 (2013.01) [G10K 11/17881 (2018.01); G10K 2210/3045 (2013.01); G10K 2210/3219 (2013.01); H04R 1/1083 (2013.01)] 22 Claims
OG exemplary drawing
 
11. A helmet comprising an active noise cancellation (ANC) system for attenuating sound pressure in a first frequency range in a defined spatial region at a first side of the helmet, comprising:
a loudspeaker disposed in a recess in an inner layer of the helmet;
a plate, a first face of the plate disposed against the inner surface of the helmet, the plate disposed over the recess such that the plate and the inner layer form a chamber containing the loudspeaker, such that the plate forms a first wall of the chamber and the inner layer of the helmet forms a second wall of the chamber, the plate having an aperture allowing transmission of sound from the loudspeaker to the defined spatial region;
at least one microphone for measuring the sound pressure; and
an ANC control system for determining, based on output signals from the at least one microphone, a drive signal for driving the loudspeaker to generate a sound signal that at least partially attenuates, in the defined spatial region and in the first frequency range, sound signals from at least one noise source.