A study on noise reduction in In-Ear microphone using two microphones

Abstract

When making a phone call on smartphone signal comes together with noise around your phone. People experience difficulties due to this outside noise. So In-Ear microphone is developed to improve this inconvenience. Because its microphone is located inside the external auditory meatus no outside noise can come through. However, as this microphone is placed inside the small external auditory meatus area there occurs distortion in low frequency part of the first formant and thus, intelligibility decreases. To improve this intelligibility was improved by partially accepting external sound using outside microphone. However, due to the external microphone some of outside noise comes through. Therefore, this research has removed noise by applying suggested method. First of all, spectral subtraction method was used to remove noise. To remove noise completely, secondly, noise was removed by using wiener filter. Based on the experiment the following result was obtained. In SNR 60dB in the background noise the average PESQ was 3.42 and in the SNR 40 dB the average PESQ was 3.68. This means that intelligibility has increased and most of noises are removed. © 2014 International Information Institute.