Scientific context and motivation

The quality of life of human beings is seriously impacted by loss of hearing. The population of Romania is rapidly aging and a sizable percentage of people over 65 years of age have a significant hearing problem. Also, the hearing health of young Romanians exposed to prolonged music listening using mobile phones or portable stereo devices at loud volume is affected. There is a worldwide growing concern about these problems and significant research effort is made (e.g. at EU level) for improving the life of old people and of people with disabilities.

Motivation

The motivation of this project is to improve the performances of the digital hearing aids for the hearing-impaired persons. Therefore, the project addresses a real need impacting the quality of life of many people. While significant advances have been achieved in hearing aid design, there still is considerable user dissatisfaction with commercially available hearing aids. In 2010 a study shows that only 69 % were happy with their performance with whistling and feedback, 61% with their behavior in noisy situations and 58% in case of wind noise.

Scientific Context

Hearing aids suffer from the presence of a positive feedback loop between the output transducer and microphone. This feedback reduces both the stable gain achievable in the forward path as well as the sound quality of the output. Two approaches are used to counteract the negative effect of the acoustic feedback: feedforward suppression and feedback cancellation. The most common feedforward technique is to use a notch filter whose gain is reduced in a narrow frequency band around the critical frequencies. ... more in the PDF file