Towards SNR-loss restoration in digital hearing AIDS

Loss of understanding speech in noise, known as signal to noise ratio (SNR) loss, is the largest problem of most hearing aid users today. This paper discusses the most important noise reduction (NR) agents available in current hearing aids and their ability to improve SNR-loss. Then, it is investigated how the many different NR agents can best be integrated to maximize results. A global minimization shows that a (Generalized Sidelobe Canceller) beamformer followed by single microphone NR agents is the theoretically optimal configuration. Since the performance of the different NR agents depends on the environment, it is suggested to use an environmental classifier to select the optimal combination of NR agents. Either by a fixed set of rules or by using a self training network catered to the specific SNR-loss of the hearing impaired.