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What is the difference between Audio and Sound?

September 25, 2023

In our Understanding Audio series, we’ll explore important audio concepts. In this first part, we clarify the distinction between sound and audio. Our goal is to enhance your listening experiences through deeper knowledge.

Let’s dive in to unlock the potential of sound and audio. Soon, you’ll speak like a true audiophile.

In brief, sound consists of vibrations traveling through air or other substances, like water. Audio, on the other hand, specifically refers to the electronic representation of sound. Like when your’re enjoying listening to music or a podcasts.

Now, let’s examine the difference between Audio and Sound.

What is sound? 

When we perceive sound, we’re actually detecting vibrations traveling from a source (e.g., a voice, musical instrument, or speakers) through the air to our ears. Sound moves as an audible longitudinal wave of pressure, a form of mechanical wave energy transferring through air or a medium.

Surprisingly, our sense of hearing relies more on audio than the raw sound itself. Our brains receive electrical signals mirroring the sound waves in our ears.

Sound waves have various frequencies measured in Hertz (cycles per second), causing subtle pressure and displacement changes in their medium. These waves overlap with multiple frequencies, combining to form the character of the sound.

Audible sound falls within the 20 Hz to 20,000 Hz frequency range. Infrasound denotes inaudible sound below 20 Hz, while ultrasound refers to inaudible sound above 20,000 Hz. Most humans can initially hear across this entire range. However, with age and hearing damage, especially in the high frequencies, this range diminishes.

Curves in a chart showing the original-Fletcher Munson loudnes-level contours

It’s worth mentioning that sound travels at varying speeds in different materials. Sound moves faster in water (around 1500 meters per second) than in air (about 340 meters per second). This difference occurs due to the distinct properties of water compared to air.

Interestingly, sound reaches an astonishing speed of 5960 meters per second when traveling through steel.

What is Audio?

Audio is sound that is within the acoustic range of human hearing. The distinct scientific meaning refers to sound that is within the acoustic range of the human ear. It ranges from 20Hz to 20,000Hz. Within a more technical context, audio refers to the electrical energy that represents sound. 

In the technical context, audio we often classify audio into two main categories: analog and digital. 

Analog audio

Analog audio translates sound into an AC voltage. Transducers play a role in converting sound to audio and back. You can manipulate analog audio for playback in different ways, like using tape or vinyl. Analog synthesizers also generate this type of audio.

However, it’s essential to maintain your analog equipment properly because magnetic tape and mechanical vinyl can degrade over time. Every time you reproduce analog audio on vinyl and tape, some quality loss occurs.

Digital audio

Digital audio relies on binary numbers for its representation. It is similar to analog audio, except that it is discrete instead of continuous. It creates a waveform by stacking small samples of varying amplitudes. 

The most common digital audio formats:

Unlike analog signals, you can reproduce digital audio without losing any quality. To hear digital audio, you need to convert it into analog using a digital-to-analog converter. If you’re recording digital audio with a microphone, you’ll use an analog-to-digital converter to change the microphone’s analog signal into digital.

Now, concerning the speed of audio, while electricity theoretically moves at the speed of light (299,792,458 m/s in a vacuum), audio signals travel much slower in reality due to the medium they pass through. Audio cables introduce more friction than a vacuum, so audio never reaches the speed of light in practical situations.


Thanks for reading. Our series Understanding Audio aims to share some knowledge and hopefully inspire your curiosity about audio and sound. If you liked this you might find it interesting to read about our solutions for automotive here.