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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Reference tone</span></span>
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<p>A <b>reference tone</b> is a <a href="Pure_tone" title="Pure tone">pure tone</a> corresponding to a known frequency, and produced at a stable <a href="Sound_pressure_level" class="mw-redirect" title="Sound pressure level">sound pressure level</a> (volume), usually by specialized equipment.
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<div class="mw-heading mw-heading2"><h2 id="In_media">In media</h2></div>
<p>The most common reference tone in <a href="Audio_engineering" class="mw-redirect" title="Audio engineering">audio engineering</a> is a <span class="ext-phonos"><span data-nosnippet="" id="ooui-php-1" class="noexcerpt ext-phonos-PhonosButton oo-ui-widget oo-ui-widget-enabled oo-ui-buttonElement oo-ui-buttonElement-frameless oo-ui-iconElement oo-ui-labelElement oo-ui-buttonWidget" data-ooui="{"_":"mw.Phonos.PhonosButton","href":"\/\/upload.wikimedia.org\/wikipedia\/commons\/transcoded\/1\/17\/1000Hz.ogg\/1000Hz.ogg.mp3","rel":["nofollow"],"framed":false,"icon":"volumeUp","label":{"html":"1000 Hz tone"},"data":{"ipa":"","text":"","lang":"en","wikibase":"","file":"1000Hz.ogg"},"classes":["noexcerpt","ext-phonos-PhonosButton"]}"><a role="button" tabindex="0" href="https://upload.wikimedia.org/wikipedia/commons/transcoded/1/17/1000Hz.ogg/1000Hz.ogg.mp3" rel="nofollow" aria-label="Play audio" title="Play audio" class="oo-ui-buttonElement-button"><span class="oo-ui-labelElement-label">1000 Hz tone</span></a></span><sup class="ext-phonos-attribution noexcerpt navigation-not-searchable">ⓘ</sup></span> at −20<a href="Decibel" title="Decibel">dB</a>. It is meant to be used by audio engineers in order to adjust the playback equipment so that the accompanying <a href="Electronic_media" title="Electronic media">media</a> is at a comfortable volume for the audience. In <a href="Video_production" title="Video production">video production</a>, this tone is usually accompanied by a <a href="Test_card" title="Test card">test card</a> so the video programming may be calibrated as well. It is sometimes played in sequence between a 100 Hz and 10 kHz tone to ensure an accurate response from the equipment at varying audio frequencies. This is also the <a href="Bleep_censor" title="Bleep censor">"bleep" tone</a> commonly used to <a href="Censorship" title="Censorship">censor</a> obscene or sensitive audio content.
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<div class="mw-heading mw-heading2"><h2 id="In_music">In music</h2></div>
<p>Many <a href="Electronic_tuner" title="Electronic tuner">electronic tuners</a> used by musicians emit a tone of <a href="A440_(pitch_standard)" title="A440 (pitch standard)">440Hz</a>, corresponding to a <a href="Pitch_(music)" title="Pitch (music)">pitch</a> of A above <a href="Middle_C" class="mw-redirect" title="Middle C">Middle C</a> (A4). More sophisticated tuners offer a choice of other reference pitches to account for differences in <a href="Musical_tuning" title="Musical tuning">tuning</a>. Some specialized tuners offer pitches used commonly on a particular instrument (standard guitar tuning, fifth intervals for string instruments, the open tones for various brass instruments).
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<div class="mw-heading mw-heading2"><h2 id="In_telecommunications">In telecommunications</h2></div>
<p>In <a href="Telecommunication" class="mw-redirect" title="Telecommunication">telecommunication</a>, a <b>standard test tone</b> is a <a href="Pure_tone" title="Pure tone">pure tone</a> with a standardized level generally used for level alignment of single links and of links in <a href="Tandem" title="Tandem">tandem</a>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>For standardized test signal levels and frequencies, see <a href="MIL-STD-188" title="MIL-STD-188">MIL-STD-188</a>-100 for <a href="United_States_Department_of_Defense" title="United States Department of Defense">United States Department of Defense</a> (DOD) use, and the <a href="Code_of_Federal_Regulations" title="Code of Federal Regulations">Code of Federal Regulations</a> Title 47, <a href="Part_68" class="mw-redirect" title="Part 68">part 68</a> for other Government agencies.
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<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1041539562">
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</style><span class="citation FS1037C MS188"><span class="noviewer" typeof="mw:File"><span></span></span> This article incorporates <a href="Copyright_status_of_works_by_the_federal_government_of_the_United_States" title="Copyright status of works by the federal government of the United States">public domain material</a> from <style data-mw-deduplicate="TemplateStyles:r1238218222">
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</style><cite class="citation cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20220122224547/https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm"><i>Federal Standard 1037C</i></a>. <a href="General_Services_Administration" title="General Services Administration">General Services Administration</a>. Archived from <a rel="nofollow" class="external text" href="https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm">the original</a> on 2022-01-22.</cite> (in support of <a href="MIL-STD-188" title="MIL-STD-188">MIL-STD-188</a>).</span></span>
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<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><a rel="nofollow" class="external text" href="http://www.freesound.org/packsViewSingle.php?id=2103">Downloadable reference tones</a>, from <a href="The_Freesound_Project" class="mw-redirect" title="The Freesound Project">The Freesound Project</a></li></ul></div><!--htdig_noindex--><div><div class="zim-footer">
This article is issued from <a class="external text" title="Last edited on 2023-01-30" href="https://en.wikipedia.org/wiki/?title=Reference_tone&oldid=1136371995">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.
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