Browse Definitions :
Definition

audio

What is audio?

Audio is sound that is within the acoustic range of human hearing. It is the audible portion on the spectrum of sound frequencies, distinct from inaudible sounds heard by certain animals or used in science and medicine. An elephant, for example, can hear sounds at lower frequencies than humans, and porpoises can hear sounds at higher frequencies. In both cases, they hear sounds that fall outside the range of human hearing.

Sound is a form of mechanical energy that travels in waves through air and other substances. It is measured in hertz (Hz), with one Hz equal to one full wave cycle per second. Humans can hear only a portion of the full spectrum of sound frequencies. The audio portion is typically between 20 to 20,000 Hz, but aging and hearing damage can shorten this range.

Although audio has a distinct meaning in relation to sound, the term is often associated with computing and other electronic devices. Within this context, audio refers to the field of technology concerned with recording, processing, storing and delivering audible sound using electricity. Most computers, for example, now support vocal interaction through a microphone audio file, can store and run sound audio files in multiple formats, and can deliver sounds through speakers or headphones. These features represent a computer's audio capabilities.

characteristics of a sound wave
Audio travels in waves that vibrate the air to send audio in through the outer ear to the ear drum, which vibrates to send sound information to the brain for processing.

How is audible sound produced and transmitted?

Audible sound is produced by using electricity and is transmitted as either analog or digital signals:

  • This form of audio uses alternating current (AC) voltage to create a signal that coincides with the frequencies and amplitudes of the original soundwaves. An analog signal can be transmitted between devices or recorded on a medium such as vinyl or tape. The signal moves in a continuous series of waves, just like a soundwave. In fact, sound is considered a naturally occurring mechanical wave in an analog format.
  • This type of audio is a representation of sound that approximates a soundwave's patterns. The sound data is transmitted and recorded as bits (1s and 0s) and stored as binary files on devices such as flash drives, DVDs or Blu-ray discs. Digital sound data is often converted from analog to digital or from digital to analog, using devices such as analog-to-digital converters (ADCs) or digital-to-analog converters (DACs). For example, an analog signal might be captured through a microphone, converted to a digital signal, stored as a binary file, and then converted back to analog when played over a set of speakers. Most computers include sound cards that contain ADC and DAC converters.
how bone conduction headphones work
Unlike traditional headphones, which transmit audio through the ear canal, bone conduction headphones work by transmitting sound through skull bones.

How is digital audio content stored?

Today, most audio content is stored as digital data, even if its original storage format is analog, as is often the case in professional recording studios. The digital trend has given rise to a wide range of audio file types, such as those shown in the table:

File type Compressed Lossless

Advanced Audio Coding (AAC)

Yes

No

Apple Lossless Audio Codec (ALAC)

Yes

Yes

Audio Interchange File Format (AIFF)

No

Yes

Free Lossless Audio Codec (FLAC)

Yes

Yes

MPEG-1 Audio Layer 3 (MP3)

Yes

No

Ogg Vorbis (OGG)

Yes

No

Pulse-Code Modulation (PCM)

No

Yes

Waveform Audio File Format (WAV)

No

Yes

Windows Media Audio (WMA)

Yes

No

Windows Media Audio Lossless (WMA Lossless)

Yes

Yes

The Compressed column indicates whether the data is compressed when stored in the specific file format. The Lossless column indicates whether data is lost from its original uncompressed state when converted to that format. If the file type is lossless, the data is preserved, otherwise it is considered lossy, which can affect sound quality.

The table does not show all audio file types; however, the ones included here represent the more common types in use today. These formats also illustrate the variety of file types supported by the audio industry, a list that continues to evolve as the industry enhances and introduces new technologies.

See also: audio frequency, dynamic range, harmonic, A-weighted decibel, bone conduction headphones, sample rate and latency

This was last updated in December 2022

Continue Reading About audio

Networking
  • subnet (subnetwork)

    A subnet, or subnetwork, is a segmented piece of a larger network. More specifically, subnets are a logical partition of an IP ...

  • secure access service edge (SASE)

    Secure access service edge (SASE), pronounced sassy, is a cloud architecture model that bundles together network and cloud-native...

  • Transmission Control Protocol (TCP)

    Transmission Control Protocol (TCP) is a standard protocol on the internet that ensures the reliable transmission of data between...

Security
  • intrusion detection system (IDS)

    An intrusion detection system monitors (IDS) network traffic for suspicious activity and sends alerts when such activity is ...

  • cyber attack

    A cyber attack is any malicious attempt to gain unauthorized access to a computer, computing system or computer network with the ...

  • digital signature

    A digital signature is a mathematical technique used to validate the authenticity and integrity of a digital document, message or...

CIO
  • What is data privacy?

    Data privacy, also called information privacy, is an aspect of data protection that addresses the proper storage, access, ...

  • product development (new product development)

    Product development -- also called new product management -- is a series of steps that includes the conceptualization, design, ...

  • innovation culture

    Innovation culture is the work environment that leaders cultivate to nurture unorthodox thinking and its application.

HRSoftware
  • organizational network analysis (ONA)

    Organizational network analysis (ONA) is a quantitative method for modeling and analyzing how communications, information, ...

  • HireVue

    HireVue is an enterprise video interviewing technology provider of a platform that lets recruiters and hiring managers screen ...

  • Human Resource Certification Institute (HRCI)

    Human Resource Certification Institute (HRCI) is a U.S.-based credentialing organization offering certifications to HR ...

Customer Experience
  • What is an outbound call?

    An outbound call is one initiated by a contact center agent to prospective customers and focuses on sales, lead generation, ...

  • What is lead-to-revenue management (L2RM)?

    Lead-to-revenue management (L2RM) is a set of sales and marketing methods focusing on generating revenue throughout the customer ...

  • What is relationship marketing?

    Relationship marketing is a facet of customer relationship management (CRM) that focuses on customer loyalty and long-term ...

Close