This effect has to do with the frequency of the sound waves. A jet engine makes a great deal of sound energy.

Sound energy Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves.

Sounds are produced when an object vibrates. The larger instruments tend to have a deeper sound, while the smaller instruments produce a higher pitch sound. Sound energy moves through a process of vibrating air molecules, which create a chain reaction of vibrating molecules that the ear perceives as sound. Sound is a type of energy. When the listener is still far away, the waves have had the opportunity to radiate apart, so the sound is not only quieter, it is a different pitch.Sound energy relies on the ear picking up the vibrations, so the further the listener is from the source of the sound, the less vibration he will be able to feel. Likewise, whether the instrument is made from silver, brass, wood, or other materials will have an impact on the type of sound it produces and how loudly it can be played.When the air molecules around the sound waves begin to vibrate, the sound waves are carried. Sound energy is the energy produced when sound waves move outward from a vibrating object or sound source. Sound energy is a form of energy that is associated with vibrations of matter. Sound is produced when a force causes an object or substance to vibrate — the energy is transferred through the substance in a wave. When this happens, the air around the object also vibrates. Sound is energy that we can hear. The closer the listener is to the source of the sound, the closer together the sound waves are. This type of energy is actually a mechanical energy source. It is a type of kinetic energy that is made from the vibration of matter. This movement causes a chain reaction to occur as more and more air molecules are made to vibrate. Facts About Sound Energy. Typically, the energy in sound is far less than other forms of energy. These waves are sources of pressure that move through air, water, or other materials like metal or wood. These waves are sources of pressure that move through air, water, or other materials like metal or wood. It is a type of mechanical wave which means it requires an object to travel through. We've all enjoyed a musical concert before, and have probably noticed the different sizes and materials of the various instruments. These vibrations in the air travel as sound waves. That will result in less sound for the listener to hear.The size of the object that is generating the sound energy will produce different types of sound waves, based on its relative size.Since sound energy relies on a medium to carry the vibrations, sound must travel through air, water, or some other medium. Sound energy is the energy produced by vibrating sound waves. This phenomenon is known as the Doppler Effect, and is named after the scientist who proposed it, Austrian physicist Christian Doppler. This type of energy is actually a mechanical energy source. This causes the motion that carries sound waves to the ear, and the ear recognizes the waves as sound.When an emergency vehicle with a siren approaches, the listener may hear a different pattern to the siren as the object closes in.