Adaptation (acoustics)

The adaptation or adaptation (from Latin adaptare "adapt"), also hearing adjustment , describes the decrease in hearing sensitivity by a certain amount when the hearing is excited over a longer period of time with a constant frequency and level signal . The decrease in loudness perception depends on the frequency composition, the level and the duration of the signal.

The effect was first demonstrated by Georg von Békésy by applying a constant level signal to one ear and at the same time using a comparison signal that he applied to the other ear to determine the decrease in loudness as a result of the adaptation.

The adaptation process begins quickly after the start of the signal presentation and shows a steep decrease in loudness, especially in the initial phase. Their maximum is reached after about 3 to 5 minutes and then maintains a constant value with longer signal presentations. The readaption, as a regression of the original sensitivity of the ear, takes about 1 to 2 minutes.

The adaptation is seen as a kind of getting used to the sound event, which in the hair cells is a leveling off in a certain metabolism , in the area of ​​the central pathways ( auditory pathway ) represents the achievement of a certain optimization state.

literature

• Georg von Békésy: On the theory of hearing: on the determination of the stimulation area of ​​the basilar membrane corresponding to a pure tone sensation by means of symptoms of fatigue . In: Physikalische Zeitschrift . tape 30 , 1929, pp. 115-125 .