Promoting off-axis listening and preserving spatial cues with Binaural Directionality II

  • Tobias Piechowiak GN ReSound A/S, Ballerup, Denmark
  • Jesper Udesen GN ReSound A/S, Ballerup, Denmark
  • Kimi Moeller GN ReSound A/S, Ballerup, Denmark
  • Fredrik Gran GN ReSound A/S, Ballerup, Denmark
  • Andrew Dittberner GN ReSound North America, Glenview, IL, USA


Hearing in complex acoustic scenes is a challenge for hearing-impaired persons that often persists after amplification is applied even when fitted bilaterally. From a hearing aid (HA) processing point of view there can be several reasons for this. First, directional filters in a symmetric fitting can help increase signal-to-noise ratio for on-axis signals-of-interest. However, they also can render off-axis signals inaudible. Second, HA microphone location can degrade spatial cues that are important for localization and thus listening in complex acoustic scenes. Third, amplification itself, when applied independently at both ears, can affect spatial cues, mainly interaural-level-differences. Finally, changing acoustic scenes might require changing processing. In order to overcome some of these challenges we propose a bilateral fitting scheme that can be symmetric or asymmetric depending on the acoustic scene. The respective HA processing modes can be (a) omnidirectional, (b) directional, or (c) directional with preservation of spatial cues. In this study it was shown that asymmetric fitting helps improve off-axis audibility when prioritized while it provides natural sound and decreases listening effort for symmetric fitting in situations when audibility is not the main focus.


Cord, M.T., Walden, R.K., Walden, B.E., and Dyrlund, O. (2004). “Relationship between laboratory measures of directional advantage and everyday success with directional microphone hearing aids,” J. Am. Acad. Audiol., 15, 353-364.

Edmonds, B.A. and Culling, J.F. (2005). “The spatial unmasking of speech: Evidence for within-channel processing of interaural time delay,” J. Acoust. Soc. Am., 117, 3069-3078.

Edmonds, B.A. and Culling, J.F. (2006). “The spatial unmasking of speech: Evidence for better-ear listening,” J. Acoust. Soc. Am., 120, 1539-1545.

Gatehouse, S. and Noble, W. (2004). “The Speech, Spatial and Qualities of Hearing Scale (SSQ),” Int. J. Audiol., 43, 85-99.

Hoffmann, H.W., Trine, T.D., Buckley, K.M., and van Tasell, D.J. (1994). “Robust adaptive microphone array processing for hearing aids: Realistic speech enhancement,” J. Acoust. Soc. Am., 96, 759-770.

Hornsby, B.W.Y. and Ricketts, T.A. (2007). “Effects of noise source configuration on directional benefit using symmetric and asymmetric directional hearing aid fittings,” Ear Hearing, 28, 177-186.

Keidser, G., Rohrseitz, K., Dillon, H., Hamacher, V., Carter, L., Rass, U., and Convery, E. (2006). “The effect of multi-channel wide dynamic range compression, noise reduction, and the directional microphone on horizontal localization performance in hearing aid wearers,” Int. J. Audiol., 45, 563-579.

Kochkin, S. (2000). “Why my hearing aids are in the drawer: The consumer’s perspective.” Hear. J., 53, 34-42.

Nielsen, H.B. (1973). “A comparison between hearing aids with directional microphone and hearing aids with conventional microphone,” Scand. Audiol., 2, 173-176.

Van den Bogaert T., Klasen, J.K., Van Deun, L., and Wouters, J. (2006). “Horizontal localization with bilateral hearing aids: Without is better than with,” J. Acoust. Soc. Am., 119, 515-526.

Walden, B.E., Surr, R.K., Cord, M.T., Edwards, B.E., and Olson, L. (2000). “Comparison of benefits provided by different hearing aid technologies,” J. Am. Acad. Audiol., 11, 540-560.
How to Cite
PIECHOWIAK, Tobias et al. Promoting off-axis listening and preserving spatial cues with Binaural Directionality II. Proceedings of the International Symposium on Auditory and Audiological Research, [S.l.], v. 5, p. 285-292, dec. 2015. Available at: <>. Date accessed: 22 oct. 2017.
2015/4. Compensation strategies for hearing rehabilitation with hearing aids