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 also can be measured scientifically.
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 a violin does. 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 a high, shrill dog whistle that many people would be unable to hear at all. 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 begins, the high frequencies are often lost first, which is why people with hearing loss often have difficulty hearing high-pitched voices of women and children. Loss of high frequency hearing also can cause distortion of sound in the speech range.