An audiometry exam tests your ability to hear sounds. The loudness of a sound is determined by the pressure of the sound wave. The higher the pressure, the louder the sound. The pressure of sound waves is measured in decibels (dB). The softest sound a person can hear is 0 dB. A loud noise, such as a jackhammer, is about 100 dB. 

There are three types of audiometry: air conduction, bone conduction, and speech reception. 

Air conduction measures how well sound passes through the outer ear and the eardrum to the inner ear. A person wears earphones and responds when they hear a sound. 

Bone conduction measures how well sound passes from the inner ear to the brain. A person wears a headband with a small vibrating device. The device sends vibrations through the bones of the skull to the inner ear. 

Speech reception measures how well a person hears and understands words. A person is asked to repeat words that are spoken in a very soft voice. 

The results of an audiometry exam are given in an audiogram. The audiogram shows the softest sound a person can hear at each frequency (pitch). The results are given as hearing loss in decibels (dB). 

Audiometry is used to diagnose hearing loss and to find out how severe it is. It can also be used to check for changes in hearing.