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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.