The distance that sound can travel depends on what medium the sound wave has to go through. The speed of the wave affects the distance that it can travel. Temperature and atmospheric pressure also can directly affect the amount of distance a sound wave can cover.
Changes in materials, temperature and air pressure can speed up or slow down a traveling sound wave. The distance that a sound wave travels can be figured by multiplying the speed of the sound (approximately 345 meters per second under normal atmospheric conditions at a temperature of 20 degrees Celsius) by the time it takes for a person to hear it once the sound is initiated.