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2.2 FACTORS AFFECTING PROPAGATION OF SOUND There are several important factors, which affect the propagation of sound: geometric spreading, atmospheric effects, and surface effects. These are discussed separately below. 2.2.1 Geometric Spreading This refers to the spreading of sound energy as a result of the expansion of the wave fronts.
Some people with very good hearing can hear sounds down to -15 dB. If a sound reaches 85 dB or stronger, it can cause permanent damage to your hearing. The amount of time you listen to a sound affects how much damage it will cause. The quieter the sound, the longer you can listen to it safely.If the sound is very quiet, it will not cause damage even if you listen to it for a very long time; however, exposure to some common sounds can cause permanent damage.f enough of them are damaged, hearing loss results. The high frequency area of the cochlea is often damaged by loud sound. Sound pressure is measured in decibels (dB). Like a temperature scale, the decibel scale goes below zero. The average person can hear sounds down to about 0 dB, the level of rustling leaves.