(19)
(11) EP 0 192 379 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.06.1987 Bulletin 1987/23

(43) Date of publication A2:
27.08.1986 Bulletin 1986/35

(21) Application number: 86300791

(22) Date of filing: 06.02.1986
(84) Designated Contracting States:
AT BE CH DE FR GB IT LI LU NL SE

(30) Priority: 21.02.1985 GB 8504541

(71) Applicant: PLESSEY OVERSEAS LIMITED
 ()

(72) Inventor:
  • Twiney, Robert Christopher
     ()

   


(54) Improvements relating to noise reduction arrangements


(57) An active noise reduction arrangement which comprises at least one ear defender or earphone structure which embodies a small noise pick-up microphone and associated noise-cancelling transducer, in which a front cavity defined between the structure and the ear of its wearer when the arrangement is in use is coupled to a further cavity and/or source of low frequency noise-cancellation signals by means of low-pass acoustic filter means.







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