Audio Engineering Society Convention Paper Presented at the 130th Convention 2011 May 13–16 London, UK The papers at this Convention have been selected on the basis of a submitted abstract and extended precis that have been peer reviewed by at least two qualified anonymous reviewers. This convention paper has been reproduced from the author’s advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. Additional papers may be obtained by sending request and remittance to Audio Engineering Society, 60 East 42 nd Street, New York, New York 10165-2520, USA; also see www.aes.org. All rights reserved. Reproduction of this paper, or any portion thereof, is not permitted without direct permission from the Journal of the Audio Engineering Society. Perceptually Robust Headphone Equalization for Binaural Reproduction Bruno Masiero 1 , Janina Fels 1 1 Institute of Technical Acoustics, RWTH Aachen University, Germany Correspondence should be addressed to Bruno Masiero (bma@akustik.rwth-aachen.de) ABSTRACT Headphones must always be adequately equalized when used for reproducing binaural signals if they are to deliver high perceptual plausibility. However, the transfer function between headphones and ear drums (HpTF) varies quite heavily with the headphone fitting for high frequencies, thus even small displacements of the headphone after equalization will lead to irregularities in the resulting frequency response. Keeping in mind that irregularities in the form of peaks are more disturbing than equivalent valleys, a new method for designing headphone equalization filters is proposed where not the average but an upper variance limit of many measured HpTFs is inverted. Such a filter yields perceptually robust equalization since the equalized frequency response will, with high chance, differ from the ideal response only by the presence of valleys in the high frequency range. 1. INTRODUCTION The realism of binaural reproduction through head- phones significantly increases if the headphones are adequately equalized. Nevertheless, the correct equalization of headphones is still an open research topic as the equalization strongly depends on the individual coupling between headphones and the lis- teners’ ear. It can be verified that open-type headphones work as a volume cavity system up to frequencies neigh- boring 4 kHz. Above this frequency region, standing waves (or equivalently, modes) start to build up in- side the cavity and thus the resulting pressure at the listeners’ eardrums becomes strongly dependent on the headphone fitting [1, pg. 84]. The Thevenin model of the human external ear described by Møller in his seminal work on binaural technology [2] is then no longer valid for this frequency range. This effect makes a direct equalization of the headphone, where usually a microphone is briefly placed in the entrance