Modern digital hearing aids offer many advantages to hearing aid users. These include adaptive noise-reduction systems, adaptive directionality, adaptive feedback suppression, and highly flexible control of numerous amplification characteristics, including complex forms of compression. Unfortunately, digital reproduction also introduces the possibility of new forms of distortion, arising from either inappropriate adaptation to the environment or the analysis of sound into different frequency regions and subsequent re-synthesis to create a single analog signal for presentation to the hearing aid user.As the purpose of digital signal processing in hearing aids is to alter sound, it is far from straightforward to measure different types of distortion by objective means. The aim of our project was to compare the perceived sound quality of several current advanced hearing aids while they are amplifying a range of different signals. We also conducted various objective measures of distortion and signal quality to relate these objective measures to the subjective measures.
- Hearing Aids
- Frequency compression