Frequency is expressed in cycles per second, or Hertz. The higher the frequency, the higher the pitch of the sound. For example, 250 Hertz (Hz) sounds like the dripping of a faucet, while the high-pitched ringing of the telephone is about 8000 Hz.
Loudness is measured in units called decibels. Zero decibels (0 dB) doesn't mean "no sound". It is just very soft. Conversational voice level is around 65 dB, and 120 dB is very, very loud – about as loud as a jet taking off when you are standing just 25 metres away. The numbers along the side of the graph are hearing levels in decibels.
During a hearing test, an audiologist presents sounds one frequency at a time. The softest tone at which a person can hear at each frequency is marked on the audiogram at that frequency and intensity. This is called the "hearing threshold".
Your audiogram is a "picture" of your hearing. It indicates how much your hearing varies from normal and, if there is a hearing loss, where the problem might be located. There are different types and degrees of hearing loss. Depending on the part of the ear that is affected, experts generally distinguish between four main types of hearing loss: conductive hearing loss, sensorineural hearing loss, mixed hearing loss and neural hearing loss.
An audiologist or hearing specialist can help you to determine if you have a hearing loss. Depending on the degree or severity, they will recommend an appropriate solution.