Digital audio

Digital audio is a way to capture and play back sound using numbers instead of traditional methods. When we talk about digital audio, we mean turning the waves of sound into a series of numbers that a computer can understand. For example, on a CD, these numbers are taken from the sound more than 44,000 times each second, giving us very clear music and voices.

This technology changed how we make, store, and share sounds. In the 1970s and 1980s, scientists and engineers made big improvements, and by the 1990s and 2000s, digital audio started replacing older ways of recording and playing music and other sounds. Now, we can record, edit, and copy audio easily using computers and other digital devices.

When sound is captured, it starts as an electrical signal that looks like the original sound wave. Special tools called analog-to-digital converters turn this into numbers we can work with. To play it back, digital-to-analog converters change the numbers back into sound that we can hear through speakers. Because digital audio uses numbers, we can make perfect copies over and over again without losing quality, unlike older methods where each copy would get a little worse.

Overview

Digital audio technologies help us record, change, make many copies, and share sounds like songs, instruments, podcasts, and sound effects. Today, we mostly get music online thanks to digital recording and compression of data. Before digital audio, we bought music on records or cassette tapes. Now, we can buy or stream music online through services like iTunes, Apple Music, Spotify, or YouTube.

Analog audio changes sound waves into electrical signals using tools like microphones. These signals can be stored on tapes or sent over phone lines or radio. But analog audio can get noisy or distorted. Digital audio, however, can stay clear and free of errors from start to finish. When we convert audio to digital, we sample it many times per second — CD audio, for example, samples 44,100 times per second. This helps us keep the sound quality high.

History

Coding

Main articles: Audio coding format and Audio data compression

Pulse-code modulation (PCM) was created by a scientist named Alec Reeves in 1937. Later, in 1950, another scientist named C. Chapin Cutler created a new way to compress information. More advances happened in the 1970s and 1980s, leading to better sound quality in music and videos.

Recording

Main article: Digital recording

Digital recording of sound began in the 1960s. Japan was the first to release commercial digital recordings in 1971. Soon after, other countries started using digital recording too. By the 1980s, digital recording became popular, especially when the CD was introduced. This made it easier to record and mix many tracks of music together.

Telephony

Main article: Digital telephony

New technology in the 1970s helped make digital phone calls possible. This led to the creation of special chips that improved phone systems. By the 1990s, most phone networks used digital technology, making phone calls clearer and more reliable.

Technologies

Digital audio is used to send audio signals over the air. Common ways to do this include Digital audio broadcasting, Digital Radio Mondiale, HD Radio, and In-band on-channel.

For recording, digital audio can be saved on special devices like CDs, DAT, Digital Compact Cassette, and MiniDisc. It can also be stored in regular audio file formats on devices such as Hard disk recorder, Blu-ray, or DVD-Audio. You can listen to these files on smartphones, computers, or an MP3 player. The quality of digital audio is often described by its bit depth, with most formats using 16-bit, 24-bit, or 32-bit resolution.