An auditory device assembly (1) comprises an earpiece (3) having an audio output device (7) for an ear (9) of a user and an audio processing unit (11, 33). The audio processing unit (11, 33) has a hearing-test mode and an audio streaming mode. In the hearing test mode the audio processing unit (11, 33) is arranged to determine at least one ear characteristic of the ear of the user based on at least one hearing test. In the audio streaming mode the audio processing unit (11, 33) is arranged to output an audio stream via the audio output device (7). The audio processing unit (11, 33) is arranged to adjust the output of the audio stream in the audio streaming mode based on the at least one ear characteristic determined in the hearing-test mode.