Digital Audio Cables

Digital audio uses digital signals for sound reproduction. This includes analog-to-digital conversion, digital-to-analog conversion, storage, and transmission. Digital audio has emerged because of its usefulness in the recording, manipulation, mass-production, and distribution of sound. Modern distribution of music across the internet through on-line stores depends on digital recording and digital compression algorithms. Distribution of audio as data files rather than as physical objects has significantly reduced costs of distribution. All analogue audio signals are susceptible to noise and distortion, due to the inherent noise present in electronic circuits. The digital audio chain begins when an analogue audio signal is converted into electrical signals — ‘on/off’ pulses — rather than electro-mechanical signals. This "channel coding" is essential to the ability of the digital system to recreate the analogue signal upon replay. Sampling and 4-bit quantization of an analogue signal (red) using Pulse Code Modulation. Digital audio is the method of representing audio in digital form. An analog signal is converted to a digital signal at a given sampling rate and bit resolution; it may contain multiple channels (2 channels for stereo or more for surround sound). Generally speaking: the higher the sampling rate and bit resolution the more fidelity, as well as increase the amount of digital data. While the goal of both analogue and digital systems is to reproduce audio perfectly, there are several obstacles to achieving this, including digital quantization noise, which is used in the capturing circuitry, and sampling rate limits the bandwidth and its bit resolution limits the dynamic range, i.e. resolution of amplitude creation and the quantization noise, which is an example of audio with progressively worsening quantization noise.

A digital audio signal starts with an analog-to-digital converter (ADC) that converts an analog signal to a digital signal. For example, CD audio has a sampling rate of 44.1 kHz (44,100 samples per second) and 16-bit resolution for each stereo channel. Some audio signals such as those created by digital synthesis originate entirely in the digital domain, in which case analog to digital conversion does not take place. After being sampled with the ADC, the digital signal may then be altered in a process which is called digital signal processing where it may be filtered or have effects applied. The digital audio signal may then be stored or transmitted. Digital audio storage can be on a CD, an MP3 player, a hard drive, USB flash drive, CompactFlash, or any other digital data storage device. Audio data compression techniques — such as MP3, Advanced Audio Coding, Ogg Vorbis, or Flac — are commonly employed to reduce the file size. Digital audio can be streamed to other devices. The last step for digital audio is to be converted back to an analog signal with a digital-to-analog converter (DAC).

Unmixed analogue recordings are likewise usually described as ADD to denote a single generation of analogue recording. Although the first-ever digital recording of a non-classical music piece, Morrissey-Mullen's cover of the Rose Royce hit Love Don't Live Here Anymore (released 1979 as a vinyl EP) was recorded in 1978 at EMI's Abbey Road recording studios, the first entirely digitally recorded (DDD) popular music album was Ry Cooder's Bop Till You Drop, recorded in late 1978. It was unmixed, being recorded straight to a two-track 3M digital recorder in the studio. Many other top recording artists were early adherents of digital recording. Martin used digital mixing,[citation needed] however, to reduce the distortion and noise that an analogue master tape would introduce (thus ADD).