Research on Multi-channel Loudness Compensation in Digital Hearing Aids

At the present,most of digital hearing aids use the technology of multi-channel compensation.But high compensation will reduce hearing comfort,even lead to negative influence when attenuation is serious.In order to improve the listening identification of hearing-impaired listeners whose listening ability severely lost in high frequency,frequency compression and shift techniques are used for multi-channel loudness compensation.Firstly,high frequency of voice signal is compressed and shifted to the target frequency band.Then,the signal is divided into four unequal size bands via Quadrature Mirror Filter Bank.According to different hearing-impaired listeners,the identity of the signal on each band is compensated and controlled.At last,the processed signal is reconstruct using perfect reconstruction filter banks.After loudness compensation,the identity of the signal is enhanced obviously and restricted within earshot of the hearing-impaired listeners.The result of the actual test of Ling'6 tone shows that the recognition rate of the voiceless increases 30 percents than traditional method.The experiment and simulation indicate that the new method has high practical value and improves hearing level and identification of hearing-impaired listeners,especially for voice with abundant high frequency.