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Vortragender: Herr Stefan Liebich, M. Sc.
Thema: *Active Noise and Occlusion Effect Cancellation in Headphones and
Hearing Aids*
Zeit: Montag, 18. Mai 2020, 11:00 Uhr
Zoom-Meeting: https://us02web.zoom.us/j/88156655771
Meeting-ID: 881 5665 5771
Passwort: 471696
The perception of one's own voice is distorted when telephoning with
headsets, or wearing hearing aids. The reason for this is the so-called
occlusion effect. The ear canals are completely or partially closed by
the headset or hearing aid. The occlusion causes amplification of low
frequencies, and attenuation of high frequencies of one's own voice. The
unnatural perception of one's own voice and of noise caused by chewing
and swallowing are among the most common complaints of users.
Furthermore, environmental noise might impair perception. In this
thesis, both the unnatural perception of one's own voice and the
disturbance by environmental noise are tackled by novel signal
processing approaches.
The proposed solution solves the problem of the occlusion effect by
actively emiiting a compensation signal through the integrated
loudspeaker. This novel approach combines methods of active noise
cancellation (ANC, Noise Cancelling Headphone) with a personalized
design. The binaural headset contains two additional microphones per
side, one inner and one outer, to acquire signals for the calculation of
the compensation signals.
A combination of feedback and feedforward digital filters allows for
either approaching personal silence or a natural perception of one's own
voice and the surroundings.
The main contributions are:
* Novel design concept for ANC / OEC systems which are robust w.r.t.
acoustical variations of ear canals and earpiece fittings
* Novel structure for combined feedback-feedforward filters with
adaptive stability control
* Analysis of variability of acoustic front-end (headset) as well as
electronics back-end (digital signal processing incl.
AD/DA-conversion) and implications on ANC/OEC performance
* Real-time implementation, instrumental and auditive evaluations
The achieved ANC performance is comparable to that of a commercial
reference system. The OEC performance revealed in both objective
measurements and subjective listening tests, significant improvements of
the own-voice perception.
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--
Irina Ronkartz
Institute of Communication Systems (IKS)
RWTH Aachen University
Muffeter Weg 3a, 52074 Aachen, Germany
+49 241 80 26958 (phone)
ronkartz(a)iks.rwth-aachen.de
http://www.iks.rwth-aachen.de/