An
audiometer is used in standard
hearing tests to determine each
ear's
sensitivity to tones at various
frequencies.
When your hearing is tested with an audiometer, you will be asked to wear headphones connected to it. When you hear a tone, you raise your left hand, your right hand, or both, depending on which ears heard the tone.
By generating a mixed bag of tones, both high and low, quiet and somewhat louder, the technician can pinpoint any specific areas (such as "8000Hz in the right ear") which merit further investigation.