Editing High fidelity

{{short description|High-quality reproduction of sound}}
{{Other uses}}
{{redirect-distinguish|Hi-Fi|Wi-Fi|High-end audio|Hyphy}}
{{Use American English|date=September 2024}}

[[File:Lautsprecher 4-wege 2.jpg|thumb|upright|Hi-fi [[loudspeaker|speakers]] are a key component of quality audio reproduction.]]

'''High fidelity''' (often shortened to '''hi-fi''' or, rarely, '''HiFi''') is the high-quality [[reproduction of sound]].<ref>{{cite book |last=Hartley |first=H. A. |title=Audio Design Handbook |url=http://www.tech-systems-labs.com/books/hartley.pdf |archive-url=https://web.archive.org/web/20090127021505/http://www.tech-systems-labs.com/books/hartley.pdf |url-status=dead |archive-date=2009-01-27 |access-date=2009-08-08 |date=1958 |publisher=Gernsback Library |location=New York, New York |id=[[Library of Congress]] Catalog Card No. 57-9007 |pages=7, 200 |chapter=High fidelity |quote=I invented the phrase 'high fidelity' in 1927 to denote a type of sound reproduction that might be taken rather seriously by a music lover. In those days the average radio or phonograph equipment sounded pretty horrible but, as I was really interested in music, it occurred to me that something might be done about it. |ref=Hartley}}</ref> It is popular with [[audiophile]]s and [[home audio]] enthusiasts. Ideally, high-fidelity equipment has inaudible [[noise]] and [[Distortion (music)|distortion]], and a flat (neutral, uncolored) [[frequency response]] within the [[human hearing range]].<ref>{{cite web|url=http://www.hi-fiworld.co.uk/amplifiers/75-amp-tests/147-frequency-response.html|title=Frequency Response|website=Hi-FiWorld.co.uk }}</ref>

High fidelity contrasts with the lower-quality "[[lo-fi]]" sound produced by inexpensive audio equipment, [[AM radio]], or the inferior quality of sound reproduction that can be heard in recordings made until the late 1940s.

== History ==
[[Bell Laboratories]] began experimenting with various recording techniques in the early 1930s. Performances by [[Leopold Stokowski]] and the [[Philadelphia Orchestra]] were recorded in 1931 and 1932 using telephone lines between the [[Academy of Music (Philadelphia)|Academy of Music]] in Philadelphia and the Bell labs in New Jersey. Some [[multitrack recording]]s were made on optical sound film, which led to new advances used primarily by [[MGM]] (as early as 1937) and [[Twentieth Century Fox Film Corporation]] (as early as 1941). [[RCA Victor]] began recording performances by several orchestras using optical sound around 1941, resulting in higher-fidelity masters for [[78-rpm disc]]s. During the 1930s, [[Avery Fisher]], an amateur violinist, began experimenting with audio design and [[acoustics]]. He wanted to make a radio that would sound like he was listening to a live orchestra and achieve high fidelity to the original sound. After [[World War II]], [[Harry F. Olson]] conducted an experiment whereby test subjects listened to a live orchestra through a hidden variable acoustic filter. The results proved that listeners preferred high-fidelity reproduction, once the noise and distortion introduced by early sound equipment was removed.{{citation needed|date=November 2019}}

Beginning in 1948, several innovations created the conditions that made major improvements in home audio quality possible:
* [[Reel-to-reel audio tape recording]], based on technology taken from Germany after WWII, helped musical artists such as [[Bing Crosby]] make and distribute recordings with better fidelity.
* The advent of the 33⅓ rpm [[long play]] (LP) microgroove [[vinyl record]], with lower [[surface noise]] and quantitatively specified [[RIAA equalization|equalization curves]] as well as noise-reduction and dynamic range systems. [[Classical music]] fans, who were [[opinion leaders]] in the audio market, quickly adopted LPs because, unlike with older records, most classical works would fit on a single LP.
* Higher quality [[turntables]], with more responsive [[phonograph#|needles]]
* [[FM radio]], with wider audio bandwidth and less susceptibility to signal interference and fading than [[AM radio]].
* Better [[amplifier]] designs, with more attention to frequency response and much higher power output capability, reproducing audio without perceptible [[distortion]].<ref name="Lander">{{cite magazine |url=http://www.americanheritage.com/articles/magazine/ah/2006/3/2006_3_13.shtml |author=David Lander |archive-url=https://web.archive.org/web/20070223172555/http://www.americanheritage.com/articles/magazine/ah/2006/3/2006_3_13.shtml |archive-date=2007-02-23 |title=The Buyable Past: Classic Hi-Fi Components |magazine=American Heritage |date=June–July 2006}}</ref>
* New [[loudspeaker]] designs, including [[acoustic suspension]], developed by [[Edgar Villchur]] and [[Henry Kloss]] with improved bass frequency response.

In the 1950s, audio manufacturers employed the phrase ''high fidelity'' as a marketing term to describe records and equipment intended to provide faithful sound reproduction. Many consumers found the difference in quality compared to the then-standard AM radios and 78-rpm records readily apparent and bought high-fidelity phonographs and 33⅓ LPs such as [[RCA]]'s New Orthophonics and London's FFRR (Full Frequency Range Recording, a UK [[Decca Records|Decca]] system). [[Audiophile]]s focused on technical characteristics and bought individual components, such as separate turntables, radio tuners, [[phono stages]], [[preamplifier]]s, [[power amplifier]]s and loudspeakers. Some enthusiasts even assembled their loudspeaker systems, with the advent of integrated multi-speaker console systems in the 1950s, ''hi-fi'' became a generic term for home sound equipment, to some extent displacing ''phonograph'' and ''record player''.

In the late 1950s and early 1960s, the development of [[stereophonic]] equipment and recordings led to the next wave of home-audio improvement, and in common parlance ''stereo'' displaced ''hi-fi''. Records were now played on ''a stereo'' (stereophonic phonograph). In the world of the audiophile, however, the concept of ''high fidelity'' continued to refer to the goal of highly accurate sound reproduction and to the technological resources available for approaching that goal. This period is regarded as the "Golden Age of Hi-Fi", when [[vacuum tube]] equipment manufacturers of the time produced many models considered superior by modern audiophiles, and just before [[solid state (electronics)|solid state]] ([[transistor]]ized) equipment was introduced to the market, subsequently replacing tube equipment as the mainstream technology.

[[File: McIntosh MA6800.jpg|thumb|An [[integrated amplifier]] combines an audio [[preamplifier]] and [[power amplifier]] into one unit, and is an example of the "component" approach to assembling a comprehensive sound reproduction system.]]
  
In the 1960s, the [[Federal Trade Commission|FTC]] with the help of the audio manufacturers came up with a definition to identify high-fidelity equipment so that the manufacturers could clearly state if they meet the requirements and reduce misleading advertisements.<ref>{{Cite book|last=Lachenbruch|first=David|url=https://books.google.com/books?id=ewsEAAAAMBAJ&q=high+fidelity+definition&pg=PA47|title=Billboard|date=1963-03-23|publisher=Nielsen Business Media, Inc.|isbn=|location=|pages=47}}</ref>

A popular type of system for reproducing music beginning in the 1970s was the integrated [[music centre]]—which combined a phonograph turntable, AM-FM radio tuner, tape player, preamplifier, and power amplifier in one package, often sold with its own separate, detachable or integrated speakers. These systems advertised their simplicity. The consumer did not have to select and assemble individual components or be familiar with impedance and power ratings. Purists generally avoid referring to these systems as high fidelity, though some are capable of very good quality sound reproduction.

Audiophiles in the 1970s and 1980s preferred to buy each component separately. That way, they could choose models of each component with the specifications that they desired. In the 1980s, several audiophile magazines became available, offering reviews of components and articles on how to choose and test speakers, amplifiers, and other components.

== Listening tests ==
{{See also|Codec listening test}}
Listening tests are used by hi-fi manufacturers, audiophile magazines, and [[audio engineering]] researchers and scientists. If a listening test is done in such a way that the listener who is assessing the sound quality of a component or recording can see the components that are being used for the test (e.g., the same musical piece listened to through a tube power amplifier and a solid-state amplifier), then it is possible that the listener's pre-existing biases towards or against certain components or brands could affect their judgment. To respond to this issue, researchers began to use [[Blinded experiment|blind tests]], in which listeners cannot see the components being tested. A commonly used variant of this test is the [[ABX test]]. A subject is presented with two known samples (sample ''A'', the reference, and sample ''B'', an alternative), and one unknown sample ''X,'' for three samples total. ''X'' is randomly selected from ''A'' and ''B'', and the subject identifies ''X'' as being either ''A'' or ''B''. Although there is no way to prove that a certain methodology is [[Transparency (data compression)|transparent]],<ref>{{cite book|author=Spanos, Aris|year=1999|title= Probability Theory and Statistical Inference |publisher= Cambridge University Press |page=699 |isbn= 0-521-42408-9}}</ref> a properly conducted double-blind test can prove that a method is ''not'' transparent.

Blind tests are sometimes used as part of attempts to ascertain whether certain audio components (such as expensive, exotic cables) have any subjectively perceivable effect on sound quality. Data gleaned from these blind tests is not accepted by some audiophile magazines such as ''[[Stereophile]]'' and ''[[The Absolute Sound]]'' in their evaluations of audio equipment. [[John Atkinson (music editor)|John Atkinson]], current editor of ''Stereophile'', stated that he once purchased a solid-state amplifier, the Quad 405, in 1978 after seeing the results from blind tests, but came to realize months later that "the magic was gone" until he replaced it with a tube amp.<ref>{{cite web |url=http://www.stereophile.com/asweseeit/705awsi |date=2005-07-17 |author=John Atkinson |title=Blind Tests & Bus Stops}}</ref> Robert Harley of ''The Absolute Sound'' wrote, in 2008, that: "...blind listening tests fundamentally distort the listening process and are worthless in determining the audibility of a certain phenomenon."<ref>{{cite web|url=http://www.avguide.com/forums/blind-listening-tests-are-flawed-editorial?page=2 |author=Robert Harley |title=Blind Listening Tests are Flawed: An Editorial |publisher=The Absolute Sound |date=2008-05-28 |access-date=2011-09-29 |url-status=dead |archive-url=https://web.archive.org/web/20110930084747/http://www.avguide.com/forums/blind-listening-tests-are-flawed-editorial?page=2 |archive-date=2011-09-30 }}</ref>

Doug Schneider, editor of the online Soundstage network, argued the opposite in 2009.<ref>{{cite web|url=http://www.goodsound.com/editorial/200905.htm |author=Doug Schneider |title=The Misinformed Misleading the Uninformed – A Bit About Blind Listening Tests |publisher=GoodSound! |date=2009-05-01 |access-date=2011-09-29}}</ref><ref>{{cite web|url=http://www.goodsound.com/editorial/200906.htm |author=Doug Schneider |title=A Bit More About Blind Listening Tests (6/2009) |publisher=GoodSound! |date=2009-06-01 |access-date=2011-09-29}}</ref>  He stated: "Blind tests are at the core of the decades' worth of research into loudspeaker design done at [[National Research Council (Canada)|Canada's National Research Council]] (NRC). The NRC researchers knew that for their result to be credible within the scientific community and to have the most meaningful results, they had to eliminate bias, and blind testing was the only way to do so." Many Canadian companies such as Axiom, Energy, Mirage, Paradigm, PSB, and Revel use blind testing extensively in designing their loudspeakers. Audio professional Dr. Sean Olive of Harman International shares this view.<ref>{{cite web|author=Dr. Sean Olive |url=http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html |title=The Dishonesty of Sighted Listening Tests |date=2009-04-09 |access-date=2011-09-29}}{{self-published inline|date=May 2020}}</ref>

==Semblance of realism==
[[Stereophonic]] sound provided a partial solution to the problem of reproducing the sound of live orchestral performers by creating separation among instruments, the [[auditory illusion#In music|illusion]] of space, and a phantom central channel. An attempt to enhance reverberation was tried in the 1970s through [[quadraphonic sound]]. Consumers did not want to pay the additional costs and space required for the marginal improvements in realism. With the rise in popularity of [[home theater]], however, multi-channel playback systems became popular, and many consumers were willing to tolerate the six to eight channels required in a home theater.

In addition to spatial realism, the playback of music must be subjectively free from noise, such as hiss or hum, to achieve realism. The [[compact disc]] (CD) provides about 90 [[decibel]]s of [[dynamic range]],<ref name="Fries2005">{{cite book |title=Digital Audio Essentials |last=Fries |first=Bruce |author2=Marty Fries |year=2005 |publisher=O'Reilly Media |isbn=0-596-00856-2 |pages=[https://archive.org/details/digitalaudioesse0000frie/page/144 144]–147 |url=https://archive.org/details/digitalaudioesse0000frie |url-access=registration |quote=Digital audio at 16-bit resolution has a theoretical dynamic range of 96 dB, but the actual dynamic range is usually lower because of overhead from filters that are built into most audio systems." ... "Audio CDs achieve about a 90-dB signal-to-noise ratio." "Most adults can't hear frequencies higher than 15&nbsp;kHz, so the 44.1&nbsp;kHz sampling rate of CD audio is more than adequate to reproduce the highest frequencies most people can hear.}}</ref> which exceeds the 80&nbsp;dB dynamic range of music as normally perceived in a concert hall.<ref>{{cite book |title=Handbook of Recording Engineering |last=Eargle |first=John |author-link=John M. Eargle |year=2005 |publisher=Springer |isbn=0-387-28470-2 |page=4 |url=https://books.google.com/books?id=00m1SlorUcIC&pg=PA4 }}</ref> Audio equipment must be able to reproduce frequencies high enough and low enough to be realistic. The human hearing range, for healthy young persons, is 20&nbsp;Hz to 20,000&nbsp;Hz.<ref>{{cite web
| url=https://hypertextbook.com/facts/2003/ChrisDAmbrose.shtml
| title=Frequency range of human hearing
| first=Christoper
| last=D'Ambrose
| year=2003
| first2=Rizwan
| last2=Choudhary
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| accessdate=2022-01-22
}}</ref> Most adults can't hear higher than 15,000&nbsp;Hz.<ref name="Fries2005"/> CDs are capable of reproducing frequencies as low as 0&nbsp;Hz and as high as 22,050&nbsp;Hz, making them adequate for reproducing the frequency range that most humans can hear.<ref name="Fries2005"/> The equipment must also provide no noticeable distortion of the [[signal]] or emphasis or de-emphasis of any frequency in this frequency range.

== Modularity {{anchor|integrated|mini|lifestyle|midi}}==
[[File:HK AVR 245.jpg|thumb|Modular components made by [[Samsung Electronics|Samsung]] and [[Harman Kardon]], (from the bottom) an audio digital receiver, DVD player, and HD TV receiver]]

[[File:Sony XO-D20S Midi HiFi system (white bg).jpg|thumb|A Sony "midi" hi-fi from the late 1980s. Despite its appearance mimicking separate components, this is an all-in-one unit featuring a record player, a dual cassette tapedeck, a digital tuner, and an amplifier with integrated equalizer. Other midi systems integrating a CD player were also increasingly common by this point.]]

''Integrated'', ''mini'', or ''lifestyle'' systems (also known by the older terms ''[[music centre]]'' or ''midi system''<ref name="argos_midi" /><ref name="matsui_midi_47" />) contain one or more sources such as a [[CD player]], a [[tuner (radio)|tuner]], or a [[cassette tape]] deck together with a [[preamplifier]] and a [[power amplifier]] in one box. A limitation of an "integrated" system is that failure of any one component can possibly lead to the need to replace the entire unit, as components are not readily swapped in or out of a system merely by plugging and unplugging cables, and may not even have been made available by the manufacturer to allow piecemeal repairs.

Although some [[high-end audio]] manufacturers do produce integrated systems, such products are generally disparaged by [[audiophile]]s, who prefer to build a system from ''separates'' (or ''components''), often with each item from a different manufacturer specialising in a particular component. This provides the most flexibility for piece-by-piece [[upgrade]]s and repairs.

A preamplifier and a power amplifier in one box is called an ''[[integrated amplifier]]''; with a tuner added, it is a ''[[Receiver (radio)|receiver]]''. A monophonic power amplifier is called a ''monoblock'' and is often used for powering a [[subwoofer]]. Other modules in the system may include components like [[magnetic cartridge|cartridges]], [[tonearm]]s, hi-fi [[turntable]]s, [[digital media player]]s, [[DVD]] players that play a wide variety of discs including [[CD]]s, [[CD recorder]]s, [[MiniDisc]] recorders, hi-fi [[videocassette recorder]]s (VCRs) and [[reel-to-reel tape recorder]]s. Signal modification equipment can include [[Equalization (audio)|equalizers]] and [[Noise reduction#In audio|noise-reduction systems]].

This modularity allows the enthusiast to spend as little or as much as they want on a component to suit their specific needs, achieve a desired sound, and add components as desired. Also, failure of any component of an integrated system can render it unusable, while the unaffected components of a modular system may continue to function.  A modular system introduces the complexity of cabling multiple components and often having different [[remote control]]s for each unit.

== Modern equipment ==
{{unreferenced section|date=February 2022}}
Some modern hi-fi equipment can be digitally connected using [[fiber optic]] [[TOSLINK]] cables, [[USB]] ports (including one to play digital audio files), or [[Wi-Fi]] support.

Another modern component is the ''music server'' consisting of one or more [[computer]] [[hard drive]]s that hold music in the form of [[computer file]]s. When the music is stored in an [[audio file format]] that is [[lossless]] such as [[FLAC]], [[Monkey's Audio]] or [[WMA Lossless]], the computer playback of recorded audio can serve as an audiophile-quality source for a hi-fi system. There is now a push from certain streaming services to offer hi-fi services.

Streaming services typically have a modified dynamic range and possibly bit rates lower than audiophile standards.{{Citation needed |date=February 2024 |reason=The statement may be outdated.}} [[Tidal (service)|Tidal]] and others have launched a hi-fi tier that includes access to FLAC and [[Master Quality Authenticated]] studio masters for many tracks through the desktop version of the player. This integration is also available for high-end audio systems.

== See also ==
{{colbegin|colwidth=20em}}  
* [[Audio system measurements]]
* [[Comparison of analog and digital recording]]
* [[DIY audio]]
* [[Edwin Howard Armstrong]]  
* [[Entertainment center]]  
* [[Lo-fi music]]
* {{slink|VHS|Hi-Fi audio system}}
* [[Wife acceptance factor]]
* [[Wi-Fi]], a [[wireless]] term derived from hi-fi
{{colend}}

== References ==
{{Reflist|refs=
<ref name="argos_midi">{{cite book|url=https://www.flickr.com/photos/lavalampmuseum/3591019798/in/album-72157619081815831/|archive-url=https://web.archive.org/web/20200527084320/https://www.flickr.com/photos/lavalampmuseum/3591019798/in/album-72157619081815831/|title=Argos Catalogue Autumn/Winter 1986|publisher=Argos|pages=258–259|quote=Midi Systems [..] Scheider 2500R Remote Control Midi System [..] Amstrad MS-45 Midi System [..] Toshiba S103K Midi System [etc]|archive-date=2020-05-27|date=1986}} [https://archive.org/stream/issuu_retromash_argos-no26-1986-autumnwinter#page/n257/mode/2up Alt URL]</ref>
<ref name="matsui_midi_47">{{cite web|url=https://www.flickr.com/photos/crouchingbadger/4434629033/in/photolist-7KSCHg|title=Matsui MIDI 47|date=14 March 2010}}</ref>
}}

==Further reading==
* {{cite book |author1=Janet Borgerson |author2=Jonathan Schroeder |date=2017 |url=https://mitpress.mit.edu/9780262536011/designed-for-hi-fi-living/ |title=Designed for Hi-Fi Living: The Vinyl LP in Midcentury America |place=Cambridge, MA |publisher=MIT Press |isbn=9780262036238}}

== External links ==
{{wiktionary|high fidelity|hi-fi|HiFi}}
* [http://www.hifi-writer.com/he/dictionary.htm A Dictionary of Home Entertainment Terms]

{{High-definition}}
{{Audio players}}

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[[Category:Sound]]
[[Category:Consumer electronics]]
[[Category:Sound recording]]
[[Category:Audio engineering]]