Sound is described in terms of frequency and intensity. Your hearing threshold is how loud the sound of a certain frequency must be for you to hear it.
Frequency, or pitch (whether a sound is low or high), is measured in vibrations per second, or hertz (Hz). The human ear can normally hear frequencies from a very low rumble of 16 Hz to a high-pitched whine of 20,000 Hz. The frequencies of normal conversations in a quiet place are 500 Hz to 2,000 Hz.
Intensity, or loudness, is measured in decibels (dB). The normal range (threshold or lower limit) of hearing is 0 dB to 25 dB. For children, the normal range is 0 dB to 15 dB. Normal results show that you hear within these ranges in both ears.
The following table relates how loud a sound must be for a person to hear it (hearing thresholds) to the degree of hearing loss for adults:
Hearing loss table
Hearing threshold in decibels (dB)
Degree of hearing loss
Ability to hear speech
No significant difficulty
Difficulty with faint or distant speech
Difficulty with conversational speech
Moderate to severe
Speech must be loud; difficulty with group conversation
Difficulty with loud speech; understands only shouted or amplified speech
May not understand amplified speech
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
Being unable to cooperate, follow directions, and understand speech well enough to respond during most tests. It may be difficult to conduct hearing tests on young children or on people who have physical or mental disabilities.
Equipment problems, such as cracked or poorly fitting headphones or an uncalibrated audiometer, or background noise.
Difficulty speaking or understanding the language of the tester.