(19)
(11) EP 1 624 719 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.04.2006 Bulletin 2006/15

(43) Date of publication A2:
08.02.2006 Bulletin 2006/06

(21) Application number: 05019858.9

(22) Date of filing: 13.09.2005
(51) International Patent Classification (IPC): 
H04R 25/00(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL BA HR MK YU

(71) Applicant: PHONAK AG
8712 Stäfa (CH)

(72) Inventor:
  • Von Buol, Andreas
    8044 Zürich (CH)

(74) Representative: Troesch Scheidegger Werner AG 
Schwäntenmos 14
8126 Zumikon
8126 Zumikon (CH)

   


(54) Method to determine a feedback threshold in a hearing device


(57) The present invention uses the fact that the gain during feedback in the forward path of a compressive system, as it is the case for a hearing device used to compensate a hearing loss, after having reached its steady state in "closed loop" operation, is equal to the feedback threshold gain (VκRIT). The steady state is reached soon after having applied a low input signal level to the hearing device, which input signal level is below 55 dB SPL (Sound Pressure Level), for example, and would result, for the open loop compressive system, in a larger gain than the feedback threshold gain of the closed loop system, respectively, would result in the maximum possible hearing device gain (Vmax) if maximum possible hearing device gain (Vmax) is below feedback threshold gain (VKRIT). The signal feedback gain is assessed in this steady state.







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