| 摘要 |
The invention relates to a hearing aid system comprising an ear-mould for a child and comprising an input transducer, a forward path, an output transducer and an electrical feedback path, the forward path comprising a signal processing unit for modifying an electrical input signal to a specific hearing profile over a predefined frequency range, wherein the predefined frequency range comprises a number of frequency bands, for which maximum forward gain values IG max for each band can be stored in a memory, the electrical feedback path comprising an adaptive filter for estimating acoustical feedback from the output to the input transducer. The invention further relates to a method of adapting a hearing aid system to varying acoustical input signals. The object of the present invention is to compensate for a mould for a child becoming too small during child growth. The object is fulfilled in that the hearing aid system further comprises an online feedback manager unit for - with a predefined update frequency - identifying current feedback gain in each frequency band of the feedback path, and for subsequently adapting the maximum forward gain values in each of the frequency bands in dependence thereof in accordance with a predefined scheme, wherein the predefined update frequency is smaller than or equal to 0.01 Hz, and wherein the relatively slow online feedback manager unit is adapted to reduce the risk of howling by decreasing the max forward gain values IG max in said ear-mould for a child. This has the advantage of avoiding feedback due to child growth. The invention may e.g. be used in digital hearing aids for use in a variety of acoustical environments. |
