An improved open-ear hearing aid to compensate for hearing loss includes a microphone 11 for picking up incident sound and converting it to an electrical audio signal. An ear insert 37 positionable within a human ear canal 35 is provided for producing an output sound amplified within one or more frequency bands in response to incident sound picked up by the microphone. The in-band gain of the amplified sound output of the ear insert's loudspeaker 29 is dependent on the user's hearing loss characteristics and the sound pressure levels of the incident sound. The form of the ear insert allows transmission of incident sound directly to the eardrum 39, where it is summed at the eardrum with the amplified sound output from the ear insert. Sound output is maximum at low incident sound pressure levels and minimum when the incident sound exceeds a set cut-off level.