Key Difference: Sound is a mechanical vibration that passes through a medium such as gas, liquid or solid to become a sound. Sound is made up of frequencies, some of which we can hear while others we can’t. Sound is technically defined as a mechanical disturbance traveling through an elastic medium. Audio can be used to refer to two things: an electric signal representing sound or an audible sound. The first definition is used to explain noise or sound that has been digitally recorded on electrical equipment. The second definition of audio refers to an audible sound, which means it can be heard by a human.

Sound and audio are two words that are often confusing as to many it refers to the same thing a noise. Hearing is one of the vital five senses in a human’s life. Without hearing, people would not be able to enjoy music, the sweet call of birds and many other things. Although, sound and audio seem similar, they are different from each other. Sound refers to vibrations caused by disruptions in a medium. Audio refers to a digital recording of a sound.

Sound is a mechanical vibration that passes through a medium such as gas, liquid or solid to become a sound. Sound is made up of frequencies, some of which we can hear while others we can’t. Sound is technically defined as a mechanical disturbance traveling through an elastic medium. The medium is not limited to air but can also include wood, metal, stone, glass and water. Sound travels in waves: mainly longitudinal and transverse waves. Longitudinal waves are waves whose direction of vibration is the same as their direction of travel. In layman’s terms the direction of the medium is the same or the opposite direction to the motion of the wave. Transverse wave is a moving wave that consist of oscillations perpendicular to the direction of the energy transfer; for example if a wave is moving in a vertical fashion, the energy transfer is moving in an horizontal fashion.

The properties of sound include: Frequency, Wavelength, Wavenumber, Amplitude, Sound pressure, Sound intensity, Speed of sound and Direction. The speed of sound is an important property that determines the speed at which sound travels. The speed of sound differs depending on the medium through which it travels. The greater the elasticity and the lower the density, the faster a sound travels. Because of this sound travels faster in solids compared to liquids and faster in liquids compared to gas. According to How Stuff Works, “At 32 °F. (0 °C.), the speed of sound in air is 1,087 feet per second (331 m/s); at 68 °F. (20 °C.), it is 1,127 feet per second (343 m/s).” The wavelength of a sound is the distance the disturbance travels in one cycle and is related to the sound’s speed and frequency. High frequency sounds have shorter wavelengths and low frequency sounds having longer wavelengths.

Audio can be used to refer to two things: an electric signal representing sound or an audible sound. The first definition is used to explain noise or sound that has been digitally recorded on electrical equipment. This definition is mostly used when audio is recorded for various purposes. Audio is commonly used to refer to an artificially generated sound such as beeping. The second definition of audio refers to an audible sound, which means it can be heard by a human. Humans can only hear certain frequencies, while other animals can hear other higher or lower frequencies. The frequencies that can be heard by humans are sometimes referred to as audio.

The second definition of audio is less commonly used compared to the first one. When defined by a dictionary, the term audio is defined as an electronic sound. It refers to any sound that has been digitally altered or created electronically. This even counts as music or speech. New computers come with audio capability, which means a feature can be activated that reads what is written on the screen for the visually impaired. This text is generated using electronics, which is why this is referred to as audio. These days audio has become a huge part of the music scene, with many people adding digital beats and music to their tracks to give it more of an edge. These songs are known as electronic music.

While sound refers to the ability of vibrations to pass through a medium and reflect off a medium. Audio is the ability to digitally create sound using electronic equipment. This is the common confusion as both are similar in nature. However, while audio is a sound, not all sound can be called as audio. 

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