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Speech Signal Enhancement for In-Ear Headphones

Authors Merz, P.
Year 2021
Thesis Type Master's thesis
Topic Audio Signal Processing
Keywords acoustics, microphone arrays, source and receiver directivity, directional microphones, directivity, signal processing
Abstract In-Ear headphones that can be used for telephony often have two microphones on the outside to enhance the user's speech signal by means of beamforming. If such an earphone also has hybrid active noise cancellation, it will also contain a third microphone on the inside, facing the ear canal. The aim of this thesis is to construct a beamforming system from the inside microphone and only one outside microphone, reducing the number of required microphones on such an earphone to two. To do so the general properties of first order microphone arrays and the attenuation of the signal arriving at the inside microphones are studied and measured. Based on the results an adaptive system is designed which compensates this attenuation for arbitrary earphone wearing conditions and maximizes the noise suppression by steering the beam pattern.
Supervisors Sontacchi, A.