An open fitting is suitable for persons with sloping hearing loss and relatively good low fre-quency hearing. Sensory neural hearing losses often have this type of configuration. A large ventilation canal gives a greater feeling of comfort and less occlusion. The purpose of this study was to look at the hearing aid benefit of open fitted hearing aids. Self report question-naires were sent out to 102 patients who were given ReSound AIR during the year of 2006 in Uddevalla.

The earmould acoustics affect the amplification that the hearing aid is programmed to give to its user. It is therefore important that the choices made for the earmould are correctly done. One choice is regarding the shape of the soundbore that affects the frequency response of the hearing aid above a certain cut-off frequency. The purpose of this project was to measure the frequency response when altering the shape of the soundbore in the earmould. Additionally, the aim was to examine how the frequency response is affected when the shape of the soundbore is not set or is not possible to set in the software when programming the hearing aid.