Audiometer
An audiometer hearing test is usually administered to a person sitting in a soundproof booth wearing a set of headphones which is connected to an audiometer. Small foam insert earphones placed in the ears may also be used. The audiometer produces tones at specific frequencies and set volume levels to each ear independently. The audiologist or licensed hearing aid specialist plots the loudness, in decibels, on an audiogram. People having their hearing tested will convey that they have heard the tone by either raising a hand or pressing a button. As the test progresses, the audiologist or hearing aid specialist, plots points on a graph where the frequency is on the x-axis and the loudness on the y-axis. Once each frequency of hearing ability is tested and plotted, the points are joined by a line so that one can see at a glance which frequencies are not being heard normally and what degree of hearing loss may be present. Normal hearing at any frequency is a sound pressure of 20 dBSPL or quieter; with worsening hearing as the number increases.
Read more about this topic: Hearing Test