Digital sound revolution
Encyclopedia
The digital sound revolution (or digital audio revolution) refers to the widespread adoption of digital audio
technology in the computer industry beginning in the 1980s.
was created in 1961 by LaFarr Stuart
, who wrote software to modulate the duration of and between pulses (pulse-width modulation
or "PWM", via a process now often referred to as "bit-banging
") on a bus line that had been connected to an amplified speaker originally installed to monitor the functioning of Iowa State University
's CYCLONE
computer, a derivative of the Illiac
. The entire computer was used to create simple, recognizable tunes using digital audio. A recording of an interview with Mr. Stuart and his computer music was broadcast nationally on the NBC
radio network
program Monitor
on February 10, 1962.
The speakers in the IBM PC
(released in 1981) and its successors may be used to create sounds and music using a similar mechanism.
. A base frequency was then modulated with analog filters to create desired effects; this process of audio waveform synthesis using frequency modulation is usually referred to as FM synthesis. This technology was introduced in the early 1980s by Yamaha
, which began manufacturing FM synth boards
for Japanese computers such as the NEC PC-8801
and PC-9801 in the early 1980s, and by 1985, the FM-7 AV
computer had built-in FM sound. This allowed personal computer game
audio to have greater complexity than the simplistic beeps
from internal speakers. These FM synth boards produced a "warm and pleasant sound" that musicians such as Yuzo Koshiro
and Takeshi Abo
utilized to produce video game music that is still highly regarded within the chiptune
community.
Early integrated circuit devices to incorporate FM synthesis methods include the Atari POKEY
custom application-specific integrated circuit
or "ASIC
" (U.S. Patent 4,314,236 issued February 2, 1982) in the Atari 800 and the MOS Technology 6581/8580 SID
chip (U.S. Patent 4,677,890, filed on February 27, 1983 and issued on July 7, 1987) used in the Commodore 64
. The Yamaha OPL2 chip set (YM3812 and external digital-to-analog converter) was included on the AdLib
sound card (1987), on the Creative Technology
Sound Blaster
(1989) and (in pairs, to create stereo sound) on the Media Vision
Pro AudioSpectrum (1991); these were replaced by the next generation Yamaha OPL3 chip set on the Pro AudioSpectrum 16 and Sound Blaster 16.
(often called "D-to-A"--abbreviated "D/A", or "DAC") integrated circuits augmented and ultimately replaced FM synthesis devices. These devices enabled computers to play digital audio using an encoding technique known as pulse-code modulation
("PCM"). Unlike pulse-width modulation
("PWM"), which turns a signal on and off, pulse-code modulation also allows the level of a signal to be set to several intermediate levels; in this regard, PWM and PCM are similar to black-and-white and grayscale images, respectively.
Digital audio compact disc
s (using PCM) were introduced in 1982. Starting in 1985, the medium was adapted for the storage of computer data via the Yellow Book
and the High Sierra Format, which became the basis for the 1988 CD-ROM
data standard ISO 9660
.
The Apple Macintosh
(1984) and Atari ST
(1985) could produce digital audio via software. Without dedicated audio hardware, digital audio on these machines were usually limited to title screens in games (at higher sampling rates) or games which did not feature heavy animation which left enough CPU time to play lower quality samples.
The first computer to feature a digital sound processor was the Commodore Amiga released in 1985. The MOS Technology
8364 Paula chip featured four independent 8-bit D/A converters. The Paula features four mono audio channels, or two combined stereo
channels. This meant for the first time a computer could play digital samples from memory with virtually no CPU
usage, or any clever software tricks.
In 1989, the Creative Technology
Sound Blaster
featured a processor and digital-to-analog converter, and incorporated the Yamaha OPL2 chip set FM synthesis devices for compatibility with the AdLib sound card. In 1991, Media Vision introduced the original Pro AudioSpectrum, which offered similar functionality but introduced stereo sound, an audio mixer and CD-ROM
interface (SCSI
and many variants); its 16-bit successor, the Pro AudioSpectrum 16, offered CD-quality sound via its 16-bit compressor-decompressor ("CODEC
").
In 1997, Intel Corporation
created its Audio CODEC
standard AC'97, which was superseded in 2004 by Intel High Definition Audio
(HD Audio).
audio hardware became inexpensive faster than data storage media, driving the development of compression techniques.
A popular early variant of pulse-code modulation
("PCM") was a compressed version called adaptive differential pulse-code modulation ("ADPCM").
Sound module file
s (originally Amiga .MOD
files) enabled music to be created and shared via compact files and played back with high quality (using four channels, each at half the sampling rate of audio compact discs). Soon after the release of its Pro AudioSpectrum 16, Media Vision included with it a MOD file player and sample music files.
In the late 1990s, the MP3
format emerged, allowing music to be stored in relatively small files by using high compressions rates through a predictive synthesis technique. Modern computer CD-ROM drives allowed the redbook audio to be read in digital format (versus earlier drives that merely output analog audio), which allows entire volumes of music to be copied and encoded many times faster than normal playback speed.
s drove competition in component sales, resulting in data storage devices becoming increasingly inexpensive. Ultimately, non-volatile semiconductor-based storage devices became less expensive than fixed hard disk drives.
) followed by widespread legitimate sales of music online through the Apple iTunes Music Store, Amazon.com
, Walmart.com and others.
Digital audio
Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...
technology in the computer industry beginning in the 1980s.
Software-based pulse-width modulation
Some of the first computer musicComputer music
Computer music is a term that was originally used within academia to describe a field of study relating to the applications of computing technology in music composition; particularly that stemming from the Western art music tradition...
was created in 1961 by LaFarr Stuart
LaFarr Stuart
LaFarr Stuart , now retired, was an early computer music pioneer, computer engineer and member of the Homebrew Computer Club.-Computer music:...
, who wrote software to modulate the duration of and between pulses (pulse-width modulation
Pulse-width modulation
Pulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....
or "PWM", via a process now often referred to as "bit-banging
Bit-banging
Bit banging is a technique for serial communications using software instead of dedicated hardware. Software directly sets and samples the state of pins on the microcontroller, and is responsible for all parameters of the signal: timing, levels, synchronization, etc...
") on a bus line that had been connected to an amplified speaker originally installed to monitor the functioning of Iowa State University
Iowa State University
Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...
's CYCLONE
CYCLONE
The CYCLONE, was an early computer built in 1959 by Iowa State University, was based on the Institute for Advanced Study architecture developed by John von Neumann...
computer, a derivative of the Illiac
ILLIAC
ILLIAC was a series of supercomputers built at a variety of locations, some at the University of Illinois at Urbana-Champaign. In all, five computers were built in this series between 1951 and 1974...
. The entire computer was used to create simple, recognizable tunes using digital audio. A recording of an interview with Mr. Stuart and his computer music was broadcast nationally on the NBC
NBC
The National Broadcasting Company is an American commercial broadcasting television network and former radio network headquartered in the GE Building in New York City's Rockefeller Center with additional major offices near Los Angeles and in Chicago...
radio network
Radio network
There are two types of radio networks currently in use around the world: the one-to-many broadcast type commonly used for public information and mass media entertainment; and the two-way type used more commonly for public safety and public services such as police, fire, taxicabs, and delivery...
program Monitor
Monitor (NBC Radio)
NBC Monitor was an American weekend radio program broadcast from June 12, 1955, until January 26, 1975. Airing live and nationwide on the NBC Radio Network, it originally aired beginning Saturday morning at 8am and continuing through the weekend until 12 midnight on Sunday...
on February 10, 1962.
The speakers in the IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
(released in 1981) and its successors may be used to create sounds and music using a similar mechanism.
FM synthesis
The first specialized audio circuits in computers included simple analog oscillators that could be set to desired frequencies, generally approximating tones along the musical scaleMusical scale
In music, a scale is a sequence of musical notes in ascending and descending order. Most commonly, especially in the context of the common practice period, the notes of a scale will belong to a single key, thus providing material for or being used to conveniently represent part or all of a musical...
. A base frequency was then modulated with analog filters to create desired effects; this process of audio waveform synthesis using frequency modulation is usually referred to as FM synthesis. This technology was introduced in the early 1980s by Yamaha
Yamaha
Yamaha may refer to:* Yamaha Corporation, a Japanese company with a wide range of products and services** Yamaha Motor Company, a Japanese motorized vehicle-producing company...
, which began manufacturing FM synth boards
Sound card
A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...
for Japanese computers such as the NEC PC-8801
NEC PC-8801
The NEC PC-8801 was an early Zilog Z80-based computer exclusively released in Japan, where it became very popular, by NEC Corporation in 1981. It was informally called the "PC-88"....
and PC-9801 in the early 1980s, and by 1985, the FM-7 AV
FM-7
FM-7 is a home computer released in 1982 in Japan.The Fujitsu FM-7 was Fujitsu's first entry into the Japanese home computer market, and for their debut computer, they chose to come out with a 6809-based personal computer very similar to Radio Shack's Color Computer.-Hardware:*Two MC 68B09 CPUs @...
computer had built-in FM sound. This allowed personal computer game
Personal computer game
A PC game, also known as a computer game, is a video game played on a personal computer, rather than on a video game console or arcade machine...
audio to have greater complexity than the simplistic beeps
Beep (sound)
A beep is a single tone onomatopoeia, generally made by a computer or a machine.-Use in computers:In some computer terminals, the ASCII character code 7, bell character, outputs an audible beep. The beep is also sometimes used to notify the user when the BIOS is not working or there is some other...
from internal speakers. These FM synth boards produced a "warm and pleasant sound" that musicians such as Yuzo Koshiro
Yuzo Koshiro
is a Japanese video game music composer and audio programmer. He is regarded as one of the most influential innovators in chiptune music and video game sound design...
and Takeshi Abo
Takeshi Abo
is a Japanese video game composer. He was employed by KID beginning in 1990, and joined 5pb. in December 2006 after KID declared bankruptcy.-Discography:*Chaos;Head*Close to ~Inori no Oka*Famicom8BIT - momo-i*Gokujyou Seitokai*Iris ~Irisu~...
utilized to produce video game music that is still highly regarded within the chiptune
Chiptune
A chiptune, also known as chip music, is synthesized electronic music often produced with the sound chips of vintage computers and video game consoles, as well as with other methods such as emulation. In the early 1980s, personal computers became cheaper and more accessible than they had previously...
community.
Early integrated circuit devices to incorporate FM synthesis methods include the Atari POKEY
Atari POKEY
The Pot Keyboard Integrated Circuit is a digital I/O chip found in the Atari 8-bit family of home computers and many arcade games in the 1980s. It was commonly used to sample potentiometers and scan matrices of switches...
custom application-specific integrated circuit
Application-specific integrated circuit
An application-specific integrated circuit is an integrated circuit customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC...
or "ASIC
ASIC
ASIC may refer to:* Application-specific integrated circuit, an integrated circuit developed for a particular use, as opposed to a customised general-purpose device.* ASIC programming language, a dialect of BASIC...
" (U.S. Patent 4,314,236 issued February 2, 1982) in the Atari 800 and the MOS Technology 6581/8580 SID
MOS Technology SID
The MOS Technology 6581/8580 SID is the built-in Programmable Sound Generator chip of Commodore's CBM-II, Commodore 64, Commodore 128 and Commodore MAX Machine home computers...
chip (U.S. Patent 4,677,890, filed on February 27, 1983 and issued on July 7, 1987) used in the Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
. The Yamaha OPL2 chip set (YM3812 and external digital-to-analog converter) was included on the AdLib
AdLib
Ad Lib, Inc. was a manufacturer of sound cards and other computer equipment founded by Martin Prevel, a former professor of music and vice-dean of the music department at the Université Laval...
sound card (1987), on the Creative Technology
Creative Technology
Creative Technology Ltd. is a Singapore-based global company headquartered in Jurong East, Singapore. The principal activities of the company and its subsidiaries consist of the design, manufacture and distribution of digitized sound and video boards, computers and related multimedia, and personal...
Sound Blaster
Sound Blaster
The Sound Blaster family of sound cards was the de facto standard for consumer audio on the IBM PC compatible system platform, until the widespread transition to Microsoft Windows 95, which standardized the programming interface at application level , and the evolution in PC design led to onboard...
(1989) and (in pairs, to create stereo sound) on the Media Vision
Media Vision
Media Vision was an American electronics manufacturer of primarily computer sound cards and CD-ROM kits, operating from 1990 to approximately 1995 in Fremont, California...
Pro AudioSpectrum (1991); these were replaced by the next generation Yamaha OPL3 chip set on the Pro AudioSpectrum 16 and Sound Blaster 16.
Digital-to-analog converters
As they became more cost-effective, digital-to-analog converterDigital-to-analog converter
In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...
(often called "D-to-A"--abbreviated "D/A", or "DAC") integrated circuits augmented and ultimately replaced FM synthesis devices. These devices enabled computers to play digital audio using an encoding technique known as pulse-code modulation
Pulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
("PCM"). Unlike pulse-width modulation
Pulse-width modulation
Pulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....
("PWM"), which turns a signal on and off, pulse-code modulation also allows the level of a signal to be set to several intermediate levels; in this regard, PWM and PCM are similar to black-and-white and grayscale images, respectively.
Digital audio compact disc
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
s (using PCM) were introduced in 1982. Starting in 1985, the medium was adapted for the storage of computer data via the Yellow Book
Yellow Book (CD standard)
The Yellow Book is the standard that defines the format of CD-ROMs. The Yellow Book, created by Sony and Philips, was the first extension of the Red Book. It is named after one of a set of color-bound books that contain the technical specifications for all CD and CD-ROM formats.-External links:The...
and the High Sierra Format, which became the basis for the 1988 CD-ROM
CD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
data standard ISO 9660
ISO 9660
ISO 9660, also referred to as CDFS by some hardware and software providers, is a file system standard published by the International Organization for Standardization for optical disc media....
.
The Apple Macintosh
Macintosh 128K
The Macintosh 128K machine, released as the "Apple Macintosh", was the original Apple Macintosh personal computer. Its beige case contained a monitor and came with a keyboard and mouse. An indentation in the top of the case made it easier for the computer to be lifted and carried. It had a selling...
(1984) and Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
(1985) could produce digital audio via software. Without dedicated audio hardware, digital audio on these machines were usually limited to title screens in games (at higher sampling rates) or games which did not feature heavy animation which left enough CPU time to play lower quality samples.
The first computer to feature a digital sound processor was the Commodore Amiga released in 1985. The MOS Technology
MOS Technology
MOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
8364 Paula chip featured four independent 8-bit D/A converters. The Paula features four mono audio channels, or two combined stereo
Stereophonic sound
The term Stereophonic, commonly called stereo, sound refers to any method of sound reproduction in which an attempt is made to create an illusion of directionality and audible perspective...
channels. This meant for the first time a computer could play digital samples from memory with virtually no CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
usage, or any clever software tricks.
In 1989, the Creative Technology
Creative Technology
Creative Technology Ltd. is a Singapore-based global company headquartered in Jurong East, Singapore. The principal activities of the company and its subsidiaries consist of the design, manufacture and distribution of digitized sound and video boards, computers and related multimedia, and personal...
Sound Blaster
Sound Blaster
The Sound Blaster family of sound cards was the de facto standard for consumer audio on the IBM PC compatible system platform, until the widespread transition to Microsoft Windows 95, which standardized the programming interface at application level , and the evolution in PC design led to onboard...
featured a processor and digital-to-analog converter, and incorporated the Yamaha OPL2 chip set FM synthesis devices for compatibility with the AdLib sound card. In 1991, Media Vision introduced the original Pro AudioSpectrum, which offered similar functionality but introduced stereo sound, an audio mixer and CD-ROM
CD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
interface (SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
and many variants); its 16-bit successor, the Pro AudioSpectrum 16, offered CD-quality sound via its 16-bit compressor-decompressor ("CODEC
Codec
A codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...
").
In 1997, Intel Corporation
Intel Corporation
Intel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...
created its Audio CODEC
Codec
A codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...
standard AC'97, which was superseded in 2004 by Intel High Definition Audio
Intel High Definition Audio
Intel High Definition Audio refers to the specification released by Intel in 2004 for delivering high-definition audio that is capable of playing back more channels at higher quality than previous integrated audio codecs like AC'97...
(HD Audio).
Compression
High fidelityHigh fidelity
High fidelity—or hi-fi—reproduction is a term used by home stereo listeners and home audio enthusiasts to refer to high-quality reproduction of sound or images, to distinguish it from the poorer quality sound produced by inexpensive audio equipment...
audio hardware became inexpensive faster than data storage media, driving the development of compression techniques.
A popular early variant of pulse-code modulation
Pulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
("PCM") was a compressed version called adaptive differential pulse-code modulation ("ADPCM").
Sound module file
Module file
Module files are a family of music file formats originating from the MOD file format on Amiga systems used in late 1980s...
s (originally Amiga .MOD
MOD (file format)
MOD is a computer file format used primarily to represent music, and was the first module file format. MOD files use the “.MOD” file extension, except on the Amiga where the original trackers instead use a “mod.” prefix scheme, e.g. “mod.echoing”...
files) enabled music to be created and shared via compact files and played back with high quality (using four channels, each at half the sampling rate of audio compact discs). Soon after the release of its Pro AudioSpectrum 16, Media Vision included with it a MOD file player and sample music files.
In the late 1990s, the MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...
format emerged, allowing music to be stored in relatively small files by using high compressions rates through a predictive synthesis technique. Modern computer CD-ROM drives allowed the redbook audio to be read in digital format (versus earlier drives that merely output analog audio), which allows entire volumes of music to be copied and encoded many times faster than normal playback speed.
Non-moving storage
After the year 2000, strong demand for small portable music players such as Apple's iPodIPod
iPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
s drove competition in component sales, resulting in data storage devices becoming increasingly inexpensive. Ultimately, non-volatile semiconductor-based storage devices became less expensive than fixed hard disk drives.
Online music distribution
The popularity of high-quality compressed music and the widespread availability of Internet access enabled widespread copyright infringement (most notably through NapsterNapster
Napster is an online music store and a Best Buy company. It was originally founded as a pioneering peer-to-peer file sharing Internet service that emphasized sharing audio files that were typically digitally encoded music as MP3 format files...
) followed by widespread legitimate sales of music online through the Apple iTunes Music Store, Amazon.com
Amazon.com
Amazon.com, Inc. is a multinational electronic commerce company headquartered in Seattle, Washington, United States. It is the world's largest online retailer. Amazon has separate websites for the following countries: United States, Canada, United Kingdom, Germany, France, Italy, Spain, Japan, and...
, Walmart.com and others.