Dynamic free-field headphone as hearing aid transducer. A preliminary report

A comparison between a body-worn hearing aid with a conventional earphone/earmould system, and a free-field dynamic headphone demonstrated the significance of the coupling between the hearing aid earphone and the subject's ear. Measurement of the insertion gain revealed destruction of the ear-canal resonance with a conventional earmould, whereas the ear-canal resonance was preserved by the use of a dynamic headphone. The use of a body-worn hearing aid connected to a dynamic headphone showed a greater amplification at low as well as at high frequencies. Furthermore, a significantly better discrimination score and an improved sound quality were demonstrated with the dynamic headphone.