Development of Novel Hearing Aid Technologies

This thesis aims to investigate alternative design approaches and apply scientific knowledge to the mechanical design of universally fitting hearing aid products. Issues related to universal hearing aid design have been identified and the areas of shape design and venting have been explored. Proposed is an alternative multiple venting configuration incorporating multiple small acoustic vent paths. In order to design universal hearing aid products one must first have an understanding of the variation in ear shape of the population. A statistical shape model has been employed to study the shape variation within a set of 60 left and 49 right ears. From this, a set of quantified design requirements of a universally fitting hearing aid product have been identified. The sound transmission properties of multi-vented samples have been tested in a custom 2cc coupler. The effects of vent number, size and length as well as sample material have been investigated. Additional small scale real ear testing has been performed to assess the real ear effects of multiple venting configurations. Finally, a 3D CAD model is given outlining how a multiple vented hearing aid may be achieved and the spatial design advantages provided. Results show, with increasing vent number and vent diameter there is an upward shift in vent associated resonance. Decreasing vent number, decreases the magnitude of the vent resonances observed. In general, smaller vents require greater area to exhibit similar low frequency transmission properties, but are less prone to vent associated Helmholtz resonances. High frequency attenuation important for feedback performance is found to be dependent on total vent area, but not on the size of the vents used. We would expect multiple vented earmoulds to have similar feedback performance but poorer occlusion performance to traditional single vented samples with the same area of venting. However, although multiple venting may require a greater amount of physical space, the small nature of the multiple vents means that there are more options to how these vents may be used. This design flexibility has been identified as the major advantage of multiple venting configurations.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2014

Author dc:creator

• Stevenson, Daniel

Advisors dc:contributor.advisor

• Xu, X
• Searchfield, G
• Taylor, M

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/21864

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/21864