As the exposure time to loud noise increases, more and more nerve endings are destroyed, As the number of nerve endings decreases, so does your hearing. People differ in their sensitivity to noise. As a general rule, noise may damage your hearing if you have to shout over background noise to make yourself heard, the noise hurts your ears, it makes your ears ring, or you are slightly deaf for several hours after exposure to the noise. Sound can be measured scientifically in two ways. Intensity, or loudness of sound, is measured in decibels.
Pitch is measured in frequency of sound vibrations per second.
A low pitch such as a deep voice or a tuba makes fewer vibrations per second than a high voice or violin. The higher the pitch of the sound, the higher the frequency, Young children, who generally have the best hearing, can often distinguish sounds from about 20 Hz, such as the lowest note on a large pipe organ, to 20,000 Hz, such as the high shrill of a dog whistle that many people are unable to hear. Human speech, which ranges from 300 to 4,000 Hz, sounds louder to most people than noises at very high or very low frequencies. When hearing impairment begin, the high frequencies are often lost first, which is why people with hearing loss often have difficulty hearing the high pitched voices of women and children. Loss of high frequency hearing also can distort sound, so that speech is difficult to understand even though it can be heard.