A method for spectral transposition of speech signal applicable in profound hearing loss

Experiments that have been carried out by the authors so far point out that locating the essential components of the speech signal in a low frequency band can improve the speech intelligibility of some hearing impaired people. It is caused by the fact that such persons can maintain their hearing ability in this range of frequencies. The experiments were performed with the use of an electronic device operating in real-time with an algorithm for lowering the audio signals frequency. The satisfactory results of these tests encouraged them to run a research project that involves designing a new digital speech processor and elaborating an advanced algorithm for the spectral transposition of speech. The paper presents a new concept of a hearing aid employing the spectral transposition method. It presents the general scheme of the vocoder-based transposition of speech signals and gives a brief description of the new speech processor implementing this method.