Comparison of Acceptable Noise Level and Signal to Noise Ratio Using Directional Microphone and FM System

Abstract

The present study was taken up with the aim to evaluate the benefit of directional microphone and frequency modulation system (FM) on Acceptable Noise Level (ANL) and Signal to Noise Ratio (SNR) using two different background competing stimuli (cafeteria noise & speech babble). The study also aimed at comparing ANL and SNR across different aided conditions (hearing aid with directional microphone turned off, hearing aid with directional microphone turned on and FM system) for two different competing background stimuli. 28 individuals with moderate to moderately severe sensorineural hearing loss in the age range of 20-60 years participated in the study. ANL and SNR were measured for all the participants. Both ANL and SNR were better with the use of FM system followed by the use of directional microphone. In addition, both ANL and SNR were dependent on the noise characteristics. Temporal and spectral characteristics of various noise affected speech recognition and ANL differently. Hence, the result should be interpreted differently for different noises. Further it was observed that ANL and SNR procedures were not different. Hence it can be concluded that ANL procedure can be used as an alternative measure to SNR procedure.