Sound energy is a form of energy that is associated with the vibrations of matter. This energy is a mechanical wave, so it needs a transmission medium to pass through, such as air and water.
Although sound vibrations produce energy, the total amount of energy for even very loud sounds is minimal. A loud train engine, for example, only produces about one hundredth of a watt per square meter. Compare this to energy that comes from sunlight hitting the earth, which is about 680 watts per square meter, and it is easy to see why sound energy is not a reliable means of generating power.
The higher pressure and more intense a sound is, the more energy it produces; as the amplitude of the waves increases, so do the perception of loudness and the total energy. Sound comes from the vibrations that are produced from one object applying force to another object. Changing the transmission medium through which sound passes also changes the sound by altering the form of the sound waves. Sound travels faster through solids and liquids than it does air because the atoms through which it passes are more densely packed. This increases its energy output due to the sound being more pressurized and more intense.