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<div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Frequency characteristics of hearing and perceived volume</div> <p class="mw-empty-elt"> </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Lindos1.svg" class="mw-file-description"><img alt="Equal-loudness contours from ISO 226:2003 shown with original ISO standard." src="//upload.wikimedia.org/wikipedia/commons/thumb/4/47/Lindos1.svg/400px-Lindos1.svg.png" decoding="async" width="400" height="359" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/47/Lindos1.svg/600px-Lindos1.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/47/Lindos1.svg/800px-Lindos1.svg.png 2x" data-file-width="704" data-file-height="632" /></a><figcaption><a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a> equal-loudness contours with frequency in Hz</figcaption></figure> <p>An <b>equal-loudness contour</b> is a measure of <a href="/wiki/Sound_pressure_level" class="mw-redirect" title="Sound pressure level">sound pressure level</a>, over the <a href="/wiki/Frequency" title="Frequency">frequency</a> spectrum, for which a listener perceives a constant <a href="/wiki/Loudness" title="Loudness">loudness</a> when presented with pure steady tones.<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> The unit of measurement for loudness levels is the <a href="/wiki/Phon" title="Phon">phon</a> and is arrived at by reference to equal-loudness contours. By definition, two sine waves of differing frequencies are said to have equal-loudness level measured in phons if they are perceived as equally loud by the average young person without significant hearing impairment. </p><p>The <b>Fletcher–Munson curves</b> are one of many sets of equal-loudness contours for the human ear, determined experimentally by <a href="/wiki/Harvey_Fletcher" title="Harvey Fletcher">Harvey Fletcher</a> and Wilden A. Munson, and reported in a 1933 paper entitled "Loudness, its definition, measurement and calculation" in the <i>Journal of the Acoustical Society of America</i>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Fletcher–Munson curves have been superseded and incorporated into newer standards. The definitive curves are those defined in <b>ISO 226</b> from the <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">International Organization for Standardization</a>, which are based on a review of modern determinations made in various countries. </p><p><a href="/wiki/Amplifier" title="Amplifier">Amplifiers</a> often feature a "loudness" button, known technically as <a href="/wiki/Loudness_compensation" title="Loudness compensation">loudness compensation</a>, that boosts low and high-frequency components of the sound. These are intended to offset the apparent loudness fall-off at those frequencies, especially at lower volume levels. Boosting these frequencies produces a flatter equal-loudness contour that appears to be louder even at low volume, preventing the perceived sound from being dominated by the mid-frequencies where the ear is most sensitive. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Fletcher–Munson_curves"><span id="Fletcher.E2.80.93Munson_curves"></span>Fletcher–Munson curves</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=1" title="Edit section: Fletcher–Munson curves"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File"><a href="/wiki/File:Lindos4.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Lindos4.svg/400px-Lindos4.svg.png" decoding="async" width="400" height="359" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Lindos4.svg/600px-Lindos4.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/49/Lindos4.svg/800px-Lindos4.svg.png 2x" data-file-width="705" data-file-height="632" /></a><figcaption></figcaption></figure> <p>The first research on the topic of how the ear hears different frequencies at different levels was conducted by Fletcher and Munson in 1933. Until recently, it was common to see the term <i>Fletcher–Munson</i> used to refer to equal-loudness contours generally, even though a re-determination was carried out by Robinson and Dadson in 1956, which became the basis for an ISO 226 standard. </p><p>The generic term <i>equal-loudness contours</i> is now preferred, of which the Fletcher–Munson curves are now a sub-set,<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> and especially since a 2003 survey by ISO redefined the curves in a new standard.<sup id="cite_ref-ISO_226_4-0" class="reference"><a href="#cite_note-ISO_226-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Experimental_determination">Experimental determination</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=2" title="Edit section: Experimental determination"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Human" title="Human">human</a> auditory system is sensitive to frequencies from about 20 <a href="/wiki/Hz" class="mw-redirect" title="Hz">Hz</a> to a maximum of around 20,000 Hz, although the upper hearing limit decreases with age. Within this range, the <a href="/wiki/Human_ear" class="mw-redirect" title="Human ear">human ear</a> is most sensitive between 2 and 5 <a href="/wiki/KHz" class="mw-redirect" title="KHz">kHz</a>, largely due to the resonance of the <a href="/wiki/Ear_canal" title="Ear canal">ear canal</a> and the <a href="/wiki/Transfer_function" title="Transfer function">transfer function</a> of the <a href="/wiki/Ossicles" title="Ossicles">ossicles</a> of the middle ear. </p><p>Fletcher and Munson first measured equal-loudness contours using <a href="/wiki/Headphones" title="Headphones">headphones</a> (1933). In their study, test subjects listened to pure tones at various frequencies and over 10 dB increments in stimulus intensity. For each frequency and intensity, the listener also listened to a reference tone at 1000 Hz. Fletcher and Munson adjusted the reference tone until the listener perceived that it had the same loudness as the test tone. Loudness, being a psychological quantity, is difficult to measure, so Fletcher and Munson averaged their results over many test subjects to derive reasonable averages. The lowest equal-loudness contour represents the quietest audible tone—the <i><a href="/wiki/Absolute_threshold_of_hearing" title="Absolute threshold of hearing">absolute threshold of hearing</a></i>. The highest contour is the <i><a href="/wiki/Threshold_of_pain" title="Threshold of pain">threshold of pain</a></i>. </p><p>Churcher and King carried out a second determination in 1937, but their results and Fletcher and Munson's showed considerable discrepancies over parts of the auditory diagram.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>In 1956 <a href="/wiki/Robinson%E2%80%93Dadson_curves" title="Robinson–Dadson curves">Robinson and Dadson</a> produced a new experimental determination that they believed was more accurate. It became the basis for a standard (ISO 226) that was considered definitive until 2003, when ISO revised the standard on the basis of recent assessments by research groups worldwide. </p> <div class="mw-heading mw-heading2"><h2 id="Recent_revision_aimed_at_more_precise_determination_–_ISO_226:2023"><span id="Recent_revision_aimed_at_more_precise_determination_.E2.80.93_ISO_226:2023"></span>Recent revision aimed at more precise determination – ISO 226:2023</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=3" title="Edit section: Recent revision aimed at more precise determination – ISO 226:2023"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Perceived discrepancies between early and more recent determinations led the <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">International Organization for Standardization</a> (ISO) to revise the standard curves in ISO 226. They did this in response to recommendations in a study coordinated by the Research Institute of Electrical Communication, Tohoku University, Japan. The study produced new curves by combining the results of several studies—by researchers in Japan, Germany, Denmark, UK, and the US. (Japan was the greatest contributor with about 40% of the data.) </p><p>This has resulted in the recent acceptance of a new set of curves standardized as ISO 226:2003. The report comments on the surprisingly large differences, and the fact that the original Fletcher–Munson contours are in better agreement with recent results than the Robinson–Dadson, which appear to differ by as much as 10–15 dB, especially in the low-frequency region, for reasons not explained.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>According to the ISO report, the Robinson–Dadson results were the odd one out, differing more from the current standard than did the Fletcher–Munson curves. The report states that it is fortunate that the 40-<a href="/wiki/Phon" title="Phon">phon</a> Fletcher–Munson curve on which the <a href="/wiki/A-weighting" title="A-weighting">A-weighting</a> standard was based turns out to have been in agreement with modern determinations.<sup id="cite_ref-ISO_226_4-1" class="reference"><a href="#cite_note-ISO_226-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>The report also comments on the large differences apparent in the low-frequency region, which remain unexplained. Possible explanations are:<sup id="cite_ref-ISO_226_4-2" class="reference"><a href="#cite_note-ISO_226-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <ul><li>The equipment used was not properly calibrated.</li> <li>The criteria used for judging equal loudness at different frequencies had differed.</li> <li>Subjects were not properly rested for days in advance, or were exposed to loud noise in traveling to the tests, which tensed the <a href="/wiki/Tensor_tympani" class="mw-redirect" title="Tensor tympani">tensor tympani</a> and <a href="/wiki/Stapedius_muscle" title="Stapedius muscle">stapedius muscles</a> controlling low-frequency mechanical coupling.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Side_versus_frontal_presentation">Side versus frontal presentation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=4" title="Edit section: Side versus frontal presentation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Unreferenced_section plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>does not <a href="/wiki/Wikipedia:Citing_sources" title="Wikipedia:Citing sources">cite</a> any <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">sources</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Equal-loudness_contour" title="Special:EditPage/Equal-loudness contour">improve this section</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and <a href="/wiki/Wikipedia:Verifiability#Burden_of_evidence" title="Wikipedia:Verifiability">removed</a>.</span> <span class="date-container"><i>(<span class="date">December 2020</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>Real-life sounds from a reasonably distant source arrive as planar wavefronts. If the source of sound is directly in front of the listener, then both ears receive equal intensity, but at frequencies above about 1 kHz the sound that enters the ear canal is partially reduced by the <a href="/wiki/Head_shadow" title="Head shadow">head shadow</a>, and also highly dependent on reflection off the <a href="/wiki/Pinna_(anatomy)" class="mw-redirect" title="Pinna (anatomy)">pinna</a> (outer ear). Off-centre sounds result in increased head masking at one ear, and subtle changes in the effect of the pinna, especially at the other ear. This combined effect of head-masking and pinna reflection is quantified in a set of curves in three-dimensional space referred to as <a href="/wiki/Head-related_transfer_function" title="Head-related transfer function">head-related transfer functions</a> (HRTFs). Frontal presentation is now regarded as preferable when deriving equal-loudness contours, and the latest ISO standard is specifically based on frontal and central presentation. </p><p>Because no HRTF is involved in normal headphone listening, equal-loudness curves derived using headphones are valid only for the special case of what is called <i>side-presentation</i>, which is not how we normally hear. </p><p>The Robinson–Dadson determination used <a href="/wiki/Loudspeaker" title="Loudspeaker">loudspeakers</a>, and for a long time the difference from the Fletcher–Munson curves was explained partly on the basis that the latter used headphones. However, the ISO report actually lists the latter as using <i>compensated</i> headphones, though it doesn't make clear how Robinson–Dadson achieved <i>compensation</i>. </p> <div class="mw-heading mw-heading2"><h2 id="Headphones_versus_loudspeaker_testing">Headphones versus loudspeaker testing</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=5" title="Edit section: Headphones versus loudspeaker testing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-Unreferenced_section plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>does not <a href="/wiki/Wikipedia:Citing_sources" title="Wikipedia:Citing sources">cite</a> any <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">sources</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Equal-loudness_contour" title="Special:EditPage/Equal-loudness contour">improve this section</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and <a href="/wiki/Wikipedia:Verifiability#Burden_of_evidence" title="Wikipedia:Verifiability">removed</a>.</span> <span class="date-container"><i>(<span class="date">October 2015</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>Good headphones, well sealed to the ear, provide a flat low-frequency pressure response to the ear canal, with low distortion even at high intensities. At low frequencies, the ear is purely pressure-sensitive, and the cavity formed between headphones and ear is too small to introduce modifying resonances. Headphone testing is, therefore, a good way to derive equal-loudness contours below about 500 Hz, though reservations have been expressed about the validity of headphone measurements when determining the actual threshold of hearing, based on the observation that closing off the ear canal produces increased sensitivity to the sound of blood flow within the ear, which the brain appears to mask in normal listening conditions.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2008)">citation needed</span></a></i>]</sup> At high frequencies, headphone measurement becomes unreliable, and the various resonances of pinnae (outer ears) and ear canals are severely affected by proximity to the headphone cavity. </p><p>With speakers, the opposite is true. A flat low-frequency response is hard to obtain—except in free space high above ground, or in a very large and <a href="/wiki/Anechoic_chamber" title="Anechoic chamber">anechoic chamber</a> that is free from reflections down to 20 Hz. Until recently,<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items" title="Wikipedia:Manual of Style/Dates and numbers"><span title="The time period mentioned near this tag is ambiguous. (May 2015)">when?</span></a></i>]</sup> it was not possible to achieve high levels at frequencies down to 20 Hz without high levels of <a href="/wiki/Total_harmonic_distortion" title="Total harmonic distortion">harmonic distortion</a>. Even today, the best speakers are likely to generate around 1 to 3% of total harmonic distortion, corresponding to 30 to 40 dB below fundamental. This is not good enough, given the steep rise in loudness (rising to as much as 24 dB per octave) with frequency revealed by the equal-loudness curves below about 100 Hz. A good experimenter must ensure that trial subjects really hear the fundamental and not harmonics—especially the third harmonic, which is especially strong as a speaker cone's travel becomes limited as its suspension reaches the limit of compliance. A possible way around the problem is to use acoustic filtering, such as by resonant cavity, in the speaker setup. A flat free-field high-frequency response up to 20 kHz, on the other hand, is comparatively easy to achieve with modern speakers on-axis. These effects must be considered when comparing results of various attempts to measure equal-loudness contours. </p> <div class="mw-heading mw-heading2"><h2 id="Relevance_to_sound_level_and_noise_measurements">Relevance to sound level and noise measurements</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=6" title="Edit section: Relevance to sound level and noise measurements"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/A-weighting" title="A-weighting">A-weighting</a> curve—in widespread use for <a href="/wiki/Noise_measurement" title="Noise measurement">noise measurement</a>—is said to have been based on the 40-phon Fletcher–Munson curve. However, research in the 1960s demonstrated that determinations of equal-loudness made using pure tones are not directly relevant to our perception of noise.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> This is because the cochlea in our inner ear analyzes sounds in terms of spectral content, each "hair-cell" responding to a narrow band of frequencies known as a <a href="/wiki/Critical_band" title="Critical band">critical band</a>. The high-frequency bands are wider in absolute terms than the low-frequency bands, and therefore "collect" proportionately more power from a noise source. However, when more than one critical band is stimulated, the signals to the brain add the various bands to produce the impressions of loudness. For these reasons equal-loudness curves derived using noise bands show an upwards tilt above 1 kHz and a downward tilt below 1 kHz when compared to the curves derived using pure tones. </p><p>Various <a href="/wiki/Weighting_curve" title="Weighting curve">weighting curves</a> were derived in the 1960s, in particular as part of the <a href="/wiki/DIN" class="mw-redirect" title="DIN">DIN</a> 4550 standard for <a href="/wiki/Audio_quality_measurement" class="mw-redirect" title="Audio quality measurement">audio quality measurement</a>, which differed from the A-weighting curve, showing more of a peak around 6 kHz. These gave a more meaningful subjective measure of noise on audio equipment, especially on the newly invented <a href="/wiki/Compact_cassette" class="mw-redirect" title="Compact cassette">compact cassette</a> tape recorders with <a href="/wiki/Dolby" title="Dolby">Dolby</a> noise reduction, which were characterized by a noise spectrum dominated by the higher frequencies. </p><p><a href="/wiki/BBC_Research" class="mw-redirect" title="BBC Research">BBC Research</a> conducted listening trials in an attempt to find the best weighting curve and rectifier combination for use when measuring noise in broadcast equipment, examining the various new weighting curves in the context of noise rather than tones, confirming that they were much more valid than A-weighting when attempting to measure the subjective loudness of noise. This work also investigated the response of human hearing to tone-bursts, clicks, <a href="/wiki/Pink_noise" title="Pink noise">pink noise</a> and a variety of other sounds that, because of their brief impulsive nature, do not give the ear and brain sufficient time to respond. The results were reported in BBC Research Report EL-17 1968/8 entitled <i>The Assessment of Noise in Audio Frequency Circuits</i>. </p><p>The <a href="/wiki/ITU-R_468_noise_weighting" title="ITU-R 468 noise weighting">ITU-R 468 noise weighting</a> curve, originally proposed in <a href="/wiki/Comit%C3%A9_consultatif_international_pour_la_radio" class="mw-redirect" title="Comité consultatif international pour la radio">CCIR</a> recommendation 468, but later adopted by numerous standards bodies (<a href="/wiki/IEC" class="mw-redirect" title="IEC">IEC</a>, <a href="/wiki/British_Standards_Institution" class="mw-redirect" title="British Standards Institution">BSI</a>, <a href="/wiki/Japanese_Industrial_Standards" title="Japanese Industrial Standards">JIS</a>, <a href="/wiki/ITU" class="mw-redirect" title="ITU">ITU</a>) was based on the research, and incorporates a special <a href="/wiki/Quasi-peak_detector" title="Quasi-peak detector">quasi-peak detector</a> to account for our reduced sensitivity to short bursts and clicks.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> It is widely used by Broadcasters and audio professionals when they measure noise on broadcast paths and audio equipment, so they can subjectively compare equipment types with different noise spectra and characteristics. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=7" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 22em;"> <ul><li><a href="/wiki/A-weighting" title="A-weighting">A-weighting</a></li> <li><a href="/wiki/Audio_quality_measurement" class="mw-redirect" title="Audio quality measurement">Audio quality measurement</a></li> <li><a href="/wiki/Audiogram" title="Audiogram">Audiogram</a></li> <li><a href="/wiki/CCIR_(ITU)_468_Noise_Weighting" class="mw-redirect" title="CCIR (ITU) 468 Noise Weighting">CCIR (ITU) 468 Noise Weighting</a></li> <li><a href="/wiki/DB(A)" class="mw-redirect" title="DB(A)">dB(A)</a></li> <li><a href="/wiki/ITU-R_468_noise_weighting" title="ITU-R 468 noise weighting">ITU-R 468 noise weighting</a></li> <li><a href="/wiki/Listener_fatigue" title="Listener fatigue">Listener fatigue</a></li> <li><a href="/wiki/Luminosity_function" class="mw-redirect" title="Luminosity function">Luminosity function</a>, the same concept in vision</li> <li><a href="/wiki/Mel_scale" title="Mel scale">Mel scale</a></li> <li><a href="/wiki/Pure_tone_audiometry" class="mw-redirect" title="Pure tone audiometry">Pure tone audiometry</a></li> <li><a href="/wiki/Robinson%E2%80%93Dadson_curves" title="Robinson–Dadson curves">Robinson–Dadson curves</a></li> <li><a href="/wiki/Sound_level_meter" title="Sound level meter">Sound level meter</a></li> <li><a href="/wiki/Weighting_filter" title="Weighting filter">Weighting filter</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=8" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <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:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFSuzukiTakeshima2004" class="citation journal cs1">Suzuki, Yôiti; Takeshima, Hisashi (2004). <a rel="nofollow" class="external text" href="https://doi.org/10.1121%2F1.1763601">"Equal-loudness-level contours for pure tones"</a>. <i>The Journal of the Acoustical Society of America</i>. <b>116</b> (2): 918–933. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004ASAJ..116..918S">2004ASAJ..116..918S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1121%2F1.1763601">10.1121/1.1763601</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0001-4966">0001-4966</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15376658">15376658</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:15865914">15865914</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Journal+of+the+Acoustical+Society+of+America&rft.atitle=Equal-loudness-level+contours+for+pure+tones&rft.volume=116&rft.issue=2&rft.pages=918-933&rft.date=2004&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A15865914%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004ASAJ..116..918S&rft.issn=0001-4966&rft_id=info%3Adoi%2F10.1121%2F1.1763601&rft_id=info%3Apmid%2F15376658&rft.aulast=Suzuki&rft.aufirst=Y%C3%B4iti&rft.au=Takeshima%2C+Hisashi&rft_id=https%3A%2F%2Fdoi.org%2F10.1121%252F1.1763601&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEqual-loudness+contour" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">Fletcher, H. and Munson, W. A. "Loudness, its definition, measurement and calculation", <i>Journal of the Acoustical Society of America</i> 5, 82–108 (1933).</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://ledgernote.com/columns/mixing-mastering/fletcher-munson-curve/">"Fletcher Munson Curve: The Equal Loudness Contour of Human Hearing"</a>. <i>Ledger Note</i>. 16 November 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">November 17,</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Ledger+Note&rft.atitle=Fletcher+Munson+Curve%3A+The+Equal+Loudness+Contour+of+Human+Hearing&rft.date=2017-11-16&rft_id=https%3A%2F%2Fledgernote.com%2Fcolumns%2Fmixing-mastering%2Ffletcher-munson-curve%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEqual-loudness+contour" class="Z3988"></span></span> </li> <li id="cite_note-ISO_226-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-ISO_226_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ISO_226_4-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-ISO_226_4-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20070927210848/http://www.nedo.go.jp/itd/grant-e/report/00pdf/is-01e.pdf"><i>ISO 226:2003</i></a> <span class="cs1-format">(PDF)</span>, archived from <a rel="nofollow" class="external text" href="http://www.nedo.go.jp/itd/grant-e/report/00pdf/is-01e.pdf">the original</a> <span class="cs1-format">(PDF)</span> on September 27, 2007</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=ISO+226%3A2003&rft_id=http%3A%2F%2Fwww.nedo.go.jp%2Fitd%2Fgrant-e%2Freport%2F00pdf%2Fis-01e.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEqual-loudness+contour" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">D. W. Robinson et al., <a rel="nofollow" class="external text" href="http://www.iop.org/EJ/abstract/0508-3443/7/5/302">"A re-determination of the equal-loudness relations for pure tones"</a>, <i>Br. J. Appl. Phys.</i> <b>7</b> (1956), pp. 166–181.</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">Yôiti Suzuki, et al., <a rel="nofollow" class="external text" href="http://www.nedo.go.jp/itd/grant-e/report/00pdf/is-01e.pdf">"Precise and Full-range Determination of Two-dimensional Equal Loudness Contours"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070927210848/http://www.nedo.go.jp/itd/grant-e/report/00pdf/is-01e.pdf">Archived</a> 2007-09-27 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>.</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Bauer, B., Torick, E., <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/1161864/;jsessionid=CC0F4DC87EF30C7DA20C05DA854120C6?tp=&arnumber=1161864&isnumber=26056">"Researches in loudness measurement"</a>, <i>IEEE Transactions on Audio and Electroacoustics</i>, Vol. 14:3 (Sep 1966), pp.141–151.</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text">Ken’ichiro Masaoka, Kazuho Ono, and Setsu Komiyama, <a rel="nofollow" class="external text" href="https://www.jstage.jst.go.jp/article/ast/22/1/22_1_35/_article/-char/en">"A measurement of equal-loudness level contours for tone burst"</a>, <i>Acoustical Science and Technology</i>, Vol. 22 (2001), No. 1 pp.35–39.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=9" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <ul><li><i>Audio Engineer's Reference Book</i>, 2nd Ed., 1999, edited Michael Talbot Smith, Focal Press.</li> <li><i>An Introduction to the Psychology of Hearing</i> 5th ed, Brian C.J. Moore, Elsevier Press.</li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Equal-loudness_contour&action=edit&section=10" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=34222&scopelist=ALL">ISO Standard</a></li> <li><a rel="nofollow" class="external text" href="http://www.mp3-tech.org/programmer/docs/IS-01Y-E.pdf">Precise and Full-range Determination of Two-dimensional Equal Loudness Contours</a></li> <li><a rel="nofollow" class="external text" href="http://www.sengpielaudio.com/Fletcher-MunsonIsNotRobinson-Dadson.pdf">Fletcher–Munson is not Robinson–Dadson (PDF)</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060115001541/http://www.aist.go.jp/aist_e/latest_research/2003/20031114/20031114.html">Full Revision of International Standards for Equal-Loudness Level Contours (ISO 226)</a></li> <li><a rel="nofollow" class="external text" href="http://www.phys.unsw.edu.au/~jw/hearing.html">Test your hearing – A tool for measuring your equal-loudness contours</a></li> <li><a rel="nofollow" class="external text" href="https://lindos.co.uk/articles/equal-loudness-contours">Equal-loudness contour measurements in detail</a></li> <li><a rel="nofollow" class="external text" href="http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JASMAN000110000005002390000001&idtype=cvips&gifs=yes">Evaluation of Loudness-level weightings and LLSEL JASA</a></li> <li><a rel="nofollow" class="external text" href="http://www.aes.org/e-lib/browse.cfm?elib=11081">A Model of Loudness Applicable to Time-Varying Sounds AESJ Article</a></li></ul> <div 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title="International Organization for Standardization">ISO</a> standards <span class="nobold">by standard number</span></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div>List of <a href="/wiki/List_of_ISO_standards" title="List of ISO standards">ISO standards</a> – <a href="/wiki/List_of_ISO_romanizations" title="List of ISO romanizations">ISO romanizations</a> – <a href="/wiki/List_of_IEC_standards" title="List of IEC standards">IEC standards</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">1–9999</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO_1" title="ISO 1">1</a></li> <li><a href="/wiki/ISO_2" title="ISO 2">2</a></li> <li><a href="/wiki/Renard_series" title="Renard series">3</a></li> <li><a href="/wiki/ISO_4" title="ISO 4">4</a></li> <li><a href="/wiki/Film_speed" title="Film speed">6</a></li> <li><a href="/wiki/British_Standard_Pipe" title="British Standard Pipe">7</a></li> <li><a href="/wiki/ISO_9" title="ISO 9">9</a></li> <li><a href="/wiki/A440_(pitch_standard)" title="A440 (pitch standard)">16</a></li> <li><a href="/wiki/Renard_series" title="Renard series">17</a></li> <li><a href="/wiki/ISO_31" title="ISO 31">31</a> <ul><li><a href="/wiki/ISO_31-0" title="ISO 31-0">-0</a></li> <li><a href="/wiki/ISO_31-1" title="ISO 31-1">-1</a></li> <li><a href="/wiki/ISO_31-3" title="ISO 31-3">-3</a></li> <li><a href="/wiki/ISO_31-4" title="ISO 31-4">-4</a></li> <li><a href="/wiki/ISO_31-5" title="ISO 31-5">-5</a></li> <li><a href="/wiki/ISO_31-6" title="ISO 31-6">-6</a></li> <li><a href="/wiki/ISO_31-7" title="ISO 31-7">-7</a></li> <li><a href="/wiki/ISO_31-8" title="ISO 31-8">-8</a></li> <li><a href="/wiki/ISO_31-9" class="mw-redirect" title="ISO 31-9">-9</a></li> <li><a href="/wiki/ISO_31-10" title="ISO 31-10">-10</a></li> <li><a href="/wiki/ISO_31-11" title="ISO 31-11">-11</a></li> <li><a href="/wiki/ISO_31-12" class="mw-redirect" title="ISO 31-12">-12</a></li> <li><a href="/wiki/ISO_31-13" class="mw-redirect" title="ISO 31-13">-13</a></li></ul></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">68-1</a></li> <li><a href="/wiki/ISO_128" title="ISO 128">128</a></li> <li><a href="/wiki/ISO_216" title="ISO 216">216</a></li> <li><a href="/wiki/ISO_217" title="ISO 217">217</a></li> <li><a class="mw-selflink selflink">226</a></li> <li><a href="/wiki/British_Standard_Pipe" title="British Standard Pipe">228</a></li> <li><a href="/wiki/ISO_233" title="ISO 233">233</a></li> <li><a href="/wiki/ISO_259" title="ISO 259">259</a></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">261</a></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">262</a></li> <li><a href="/wiki/Kappa_number" title="Kappa number">302</a></li> <li><a href="/wiki/Vicat_softening_point" title="Vicat softening point">306</a></li> <li><a href="/wiki/Hazard_symbol#Ionizing_radiation_symbol" title="Hazard symbol">361</a></li> <li><a href="/wiki/Power_take-off" title="Power take-off">500</a></li> <li><a href="/wiki/Hot_shoe" title="Hot shoe">518</a></li> <li><a href="/wiki/Prontor-Compur" title="Prontor-Compur">519</a></li> <li><a href="/wiki/ISO_639" title="ISO 639">639</a> <ul><li><a href="/wiki/ISO_639-1" title="ISO 639-1">-1</a></li> <li><a href="/wiki/ISO_639-2" title="ISO 639-2">-2</a></li> <li><a href="/wiki/ISO_639-3" title="ISO 639-3">-3</a></li> <li><a href="/wiki/ISO_639-5" title="ISO 639-5">-5</a></li> <li><a href="/wiki/ISO_639-6" title="ISO 639-6">-6</a></li></ul></li> <li><a href="/wiki/ISO/IEC_646" title="ISO/IEC 646">646</a></li> <li><a href="/wiki/ISO_657" title="ISO 657">657</a></li> <li><a href="/wiki/ISO_668" title="ISO 668">668</a></li> <li><a href="/wiki/ISO_690" title="ISO 690">690</a></li> <li><a href="/wiki/ISO_704" title="ISO 704">704</a></li> <li><a href="/wiki/ISO_732" title="ISO 732">732</a></li> <li><a href="/wiki/Antimagnetic_watch" title="Antimagnetic watch">764</a></li> <li><a href="/wiki/Hole_punch" title="Hole punch">838</a></li> <li><a href="/wiki/ISO_843" title="ISO 843">843</a></li> <li><a href="/wiki/ISO_860" title="ISO 860">860</a></li> <li><a href="/wiki/ISO_898" title="ISO 898">898</a></li> <li><a href="/wiki/ISO_965" title="ISO 965">965</a></li> <li><a href="/wiki/ISO_999" title="ISO 999">999</a></li> <li><a href="/wiki/ISO_1000" title="ISO 1000">1000</a></li> <li><a href="/wiki/Magnetic_ink_character_recognition" title="Magnetic ink character recognition">1004</a></li> <li><a href="/wiki/135_film" title="135 film">1007</a></li> <li><a href="/wiki/OCR-A" title="OCR-A">1073-1</a></li> <li><a href="/wiki/OCR-B" title="OCR-B">1073-2</a></li> <li><a href="/wiki/Longitudinal_redundancy_check" title="Longitudinal redundancy check">1155</a></li> <li><a href="/wiki/Shock-resistant_watch#ISO_1413_shock-resistant_standard" title="Shock-resistant watch">1413</a></li> <li><a href="/wiki/ALGOL_60" title="ALGOL 60">1538</a></li> <li><a href="/wiki/ISO_1629" title="ISO 1629">1629</a></li> <li><a href="/wiki/ISO_1745" title="ISO 1745">1745</a></li> <li><a href="/wiki/COBOL" title="COBOL">1989</a></li> <li><a href="/wiki/ISO_2014" title="ISO 2014">2014</a></li> <li><a href="/wiki/ISO_2015" title="ISO 2015">2015</a></li> <li><a href="/wiki/ISO/IEC_2022" title="ISO/IEC 2022">2022</a></li> <li><a href="/wiki/ISO_2033" title="ISO 2033">2033</a></li> <li><a href="/wiki/ISO_2047" title="ISO 2047">2047</a></li> <li><a href="/wiki/ISBN" title="ISBN">2108</a></li> <li><a href="/wiki/ISO_2145" title="ISO 2145">2145</a></li> <li><a href="/wiki/ISO_2146" title="ISO 2146">2146</a></li> <li><a href="/wiki/Film_speed" title="Film speed">2240</a></li> <li><a href="/wiki/Water_Resistant_mark" title="Water Resistant mark">2281</a></li> <li><a href="/wiki/International_Standard_Atmosphere" title="International Standard Atmosphere">2533</a></li> <li><a href="/wiki/ISO_2709" title="ISO 2709">2709</a></li> <li><a href="/wiki/ISO_2711" title="ISO 2711">2711</a></li> <li><a href="/wiki/Film_speed" title="Film speed">2720</a></li> <li><a href="/wiki/ISO_2788" title="ISO 2788">2788</a></li> <li><a href="/wiki/ISO_2848" title="ISO 2848">2848</a></li> <li><a href="/wiki/ISO_2852" title="ISO 2852">2852</a></li> <li><a href="/wiki/ISO_2921" title="ISO 2921">2921</a></li> <li><a href="/wiki/126_film" title="126 film">3029</a></li> <li><a href="/wiki/ISO_3103" title="ISO 3103">3103</a></li> <li><a href="/wiki/ISO_3166" title="ISO 3166">3166</a> <ul><li><a href="/wiki/ISO_3166-1" title="ISO 3166-1">-1</a></li> <li><a href="/wiki/ISO_3166-2" title="ISO 3166-2">-2</a></li> <li><a href="/wiki/ISO_3166-3" title="ISO 3166-3">-3</a></li></ul></li> <li><a href="/wiki/International_Standard_Serial_Number" class="mw-redirect" title="International Standard Serial Number">3297</a></li> <li><a href="/wiki/ISO_3307" title="ISO 3307">3307</a></li> <li><a href="/wiki/O-ring" title="O-ring">3601</a></li> <li><a href="/wiki/Kunrei-shiki_romanization" title="Kunrei-shiki romanization">3602</a></li> <li><a href="/wiki/ISO_3864" title="ISO 3864">3864</a></li> <li><a href="/wiki/International_Standard_Recording_Code" title="International Standard Recording Code">3901</a></li> <li><a href="/wiki/FDI_World_Dental_Federation_notation" title="FDI World Dental Federation notation">3950</a></li> <li><a href="/wiki/ISO_3977" title="ISO 3977">3977</a></li> <li><a href="/wiki/ISO_4031" title="ISO 4031">4031</a></li> <li><a href="/wiki/ISO_4157" title="ISO 4157">4157</a></li> <li><a href="/wiki/ISO_4165" title="ISO 4165">4165</a></li> <li><a href="/wiki/ISO_4217" title="ISO 4217">4217</a></li> <li><a href="/wiki/ISO/IEC_4909" title="ISO/IEC 4909">4909</a></li> <li><a href="/wiki/ISO/IEC_5218" title="ISO/IEC 5218">5218</a></li> <li><a href="/wiki/ISO_5426" title="ISO 5426">5426</a></li> <li><a href="/wiki/ISO_5427" title="ISO 5427">5427</a></li> <li><a href="/wiki/ISO_5428" title="ISO 5428">5428</a></li> <li><a href="/wiki/Accuracy_and_precision" title="Accuracy and precision">5725</a></li> <li><a href="/wiki/ISO_5775" title="ISO 5775">5775</a></li> <li><a href="/wiki/ISO_5776" title="ISO 5776">5776</a></li> <li><a href="/wiki/Film_speed" title="Film speed">5800</a></li> <li><a href="/wiki/Flowchart" title="Flowchart">5807</a></li> <li><a href="/wiki/ISO_5964" title="ISO 5964">5964</a></li> <li><a href="/wiki/International_Securities_Identification_Number" title="International Securities Identification Number">6166</a></li> <li><a href="/wiki/ISO_6344" title="ISO 6344">6344</a></li> <li><a href="/wiki/ISO_6346" title="ISO 6346">6346</a></li> <li><a href="/wiki/Minimal_BASIC" title="Minimal BASIC">6373</a></li> <li><a href="/wiki/ISO_6385" title="ISO 6385">6385</a></li> <li><a href="/wiki/Water_Resistant_mark" title="Water Resistant mark">6425</a></li> <li><a href="/wiki/ANSI_escape_code" title="ANSI escape code">6429</a></li> <li><a href="/wiki/ISO_6438" title="ISO 6438">6438</a></li> <li><a href="/wiki/ISO/IEC_6523" title="ISO/IEC 6523">6523</a></li> <li><a href="/wiki/ISO_6709" title="ISO 6709">6709</a></li> <li><a href="/wiki/ISO_6943" title="ISO 6943">6943</a></li> <li><a href="/wiki/ISO_7001" title="ISO 7001">7001</a></li> <li><a href="/wiki/ISO_7002" title="ISO 7002">7002</a></li> <li><a href="/wiki/ISO_7010" title="ISO 7010">7010</a></li> <li><a href="/wiki/ISO_7027" title="ISO 7027">7027</a></li> <li><a href="/wiki/ISO/IEC_7064" title="ISO/IEC 7064">7064</a></li> <li><a href="/wiki/Pinyin" title="Pinyin">7098</a></li> <li><a href="/wiki/Pascal_(programming_language)" title="Pascal (programming language)">7185</a></li> <li><a href="/wiki/ISO_7200" title="ISO 7200">7200</a></li> <li><a href="/wiki/OSI_model" title="OSI model">7498</a> <ul><li><a href="/wiki/OSI_model" title="OSI model">-1</a></li></ul></li> <li><a href="/wiki/ISO_7637" title="ISO 7637">7637</a></li> <li><a href="/wiki/ISO_7736" title="ISO 7736">7736</a></li> <li><a href="/wiki/ISO/IEC_7810" title="ISO/IEC 7810">7810</a></li> <li><a href="/wiki/ISO/IEC_7811" title="ISO/IEC 7811">7811</a></li> <li><a href="/wiki/ISO/IEC_7812" title="ISO/IEC 7812">7812</a></li> <li><a href="/wiki/ISO/IEC_7813" title="ISO/IEC 7813">7813</a></li> <li><a href="/wiki/ISO/IEC_7816" title="ISO/IEC 7816">7816</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">7942</a></li> <li><a href="/wiki/ISO_8000" title="ISO 8000">8000</a></li> <li><a href="/wiki/On-board_diagnostics" title="On-board diagnostics">8093</a></li> <li><a href="/wiki/ISO_8178" title="ISO 8178">8178</a></li> <li><a href="/wiki/Fuel_oil" title="Fuel oil">8217</a></li> <li><a href="/wiki/ISO_8373" class="mw-redirect" title="ISO 8373">8373</a></li> <li><a href="/wiki/ISO_8501-1" title="ISO 8501-1">8501-1</a></li> <li><a href="/wiki/FTAM" title="FTAM">8571</a></li> <li><a href="/wiki/ISO_8583" title="ISO 8583">8583</a></li> <li><a href="/wiki/ISO_8601" title="ISO 8601">8601</a></li> <li><a href="/wiki/Open_Document_Architecture" title="Open Document Architecture">8613</a></li> <li><a href="/wiki/Computer_Graphics_Metafile" title="Computer Graphics Metafile">8632</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">8651</a></li> <li><a href="/wiki/ISO/IEC_8652" title="ISO/IEC 8652">8652</a></li> <li><a href="/wiki/ISO_8691" title="ISO 8691">8691</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">8805/8806</a></li> <li><a href="/wiki/Language_Of_Temporal_Ordering_Specification" class="mw-redirect" title="Language Of Temporal Ordering Specification">8807</a></li> <li><a href="/wiki/Fuse_(automotive)" class="mw-redirect" title="Fuse (automotive)">8820-5</a></li> <li><a href="/wiki/ISO/IEC_8859" title="ISO/IEC 8859">8859</a> <ul><li><a href="/wiki/ISO/IEC_8859-1" title="ISO/IEC 8859-1">-1</a></li> <li><a href="/wiki/ISO/IEC_8859-2" title="ISO/IEC 8859-2">-2</a></li> <li><a href="/wiki/ISO/IEC_8859-3" title="ISO/IEC 8859-3">-3</a></li> <li><a href="/wiki/ISO/IEC_8859-4" title="ISO/IEC 8859-4">-4</a></li> <li><a href="/wiki/ISO/IEC_8859-5" title="ISO/IEC 8859-5">-5</a></li> <li><a href="/wiki/ISO/IEC_8859-6" title="ISO/IEC 8859-6">-6</a></li> <li><a href="/wiki/ISO/IEC_8859-7" title="ISO/IEC 8859-7">-7</a></li> <li><a href="/wiki/ISO/IEC_8859-8" title="ISO/IEC 8859-8">-8</a></li> <li><a href="/wiki/ISO-8859-8-I" title="ISO-8859-8-I">-8-I</a></li> <li><a href="/wiki/ISO/IEC_8859-9" title="ISO/IEC 8859-9">-9</a></li> <li><a href="/wiki/ISO/IEC_8859-10" title="ISO/IEC 8859-10">-10</a></li> <li><a href="/wiki/ISO/IEC_8859-11" title="ISO/IEC 8859-11">-11</a></li> <li><a href="/wiki/ISO/IEC_8859-12" class="mw-redirect" title="ISO/IEC 8859-12">-12</a></li> <li><a href="/wiki/ISO/IEC_8859-13" title="ISO/IEC 8859-13">-13</a></li> <li><a href="/wiki/ISO/IEC_8859-14" title="ISO/IEC 8859-14">-14</a></li> <li><a href="/wiki/ISO/IEC_8859-15" title="ISO/IEC 8859-15">-15</a></li> <li><a href="/wiki/ISO/IEC_8859-16" title="ISO/IEC 8859-16">-16</a></li></ul></li> <li><a href="/wiki/Standard_Generalized_Markup_Language" title="Standard Generalized Markup Language">8879</a></li> <li><a href="/wiki/ISO_9000" class="mw-redirect" title="ISO 9000">9000/9001</a></li> <li><a href="/wiki/ASMO_449" title="ASMO 449">9036</a></li> <li><a href="/wiki/SQL" title="SQL">9075</a></li> <li><a href="/wiki/ISO/IEC_9126" title="ISO/IEC 9126">9126</a></li> <li><a href="/wiki/On-board_diagnostics" title="On-board diagnostics">9141</a></li> <li><a href="/wiki/Salt_spray_test" title="Salt spray test">9227</a></li> <li><a href="/wiki/ISO_9241" title="ISO 9241">9241</a></li> <li><a href="/wiki/File_Allocation_Table" title="File Allocation Table">9293</a></li> <li><a href="/wiki/Fiber_Distributed_Data_Interface" title="Fiber Distributed Data Interface">9314</a></li> <li><a href="/wiki/ISO_9362" title="ISO 9362">9362</a></li> <li><a href="/wiki/Shoe_size" title="Shoe size">9407</a></li> <li><a href="/wiki/CHILL" title="CHILL">9496</a></li> <li><a href="/wiki/Manufacturing_Message_Specification" title="Manufacturing Message Specification">9506</a></li> <li><a href="/wiki/ISO/IEC_9529" title="ISO/IEC 9529">9529</a></li> <li><a href="/wiki/ISO_9564" title="ISO 9564">9564</a></li> <li><a href="/wiki/PHIGS" title="PHIGS">9592/9593</a></li> <li><a href="/wiki/X.500" title="X.500">9594</a></li> <li><a href="/wiki/ISO_9660" title="ISO 9660">9660</a></li> <li><a href="/wiki/ISO/IEC_9797-1" title="ISO/IEC 9797-1">9797-1</a></li> <li><a href="/wiki/ISO_9897" title="ISO 9897">9897</a></li> <li><a href="/wiki/ANSI_C" title="ANSI C">9899</a></li> <li><a href="/wiki/POSIX" title="POSIX">9945</a></li> <li><a href="/wiki/Romanization_of_Georgian" title="Romanization of Georgian">9984</a></li> <li><a href="/wiki/Romanization_of_Armenian" title="Romanization of Armenian">9985</a></li> <li><a href="/wiki/ISO/IEC_9995" title="ISO/IEC 9995">9995</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">10000–19999</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO_10006" title="ISO 10006">10006</a></li> <li><a href="/wiki/ISO_10007" title="ISO 10007">10007</a></li> <li><a href="/wiki/ISO/IEC_10116" title="ISO/IEC 10116">10116</a></li> <li><a href="/wiki/Whirlpool_(hash_function)" title="Whirlpool (hash function)">10118-3</a></li> <li><a href="/wiki/ISO_10160" title="ISO 10160">10160</a></li> <li><a href="/wiki/ISO_10161" title="ISO 10161">10161</a></li> <li><a href="/wiki/Guidelines_for_the_Definition_of_Managed_Objects" title="Guidelines for the Definition of Managed Objects">10165</a></li> <li><a href="/wiki/Document_Style_Semantics_and_Specification_Language" title="Document Style Semantics and Specification Language">10179</a></li> <li><a href="/wiki/Pascal_(programming_language)#ISO/IEC_10206:1990_Extended_Pascal" title="Pascal (programming language)">10206</a></li> <li><a href="/wiki/ISO_10218" title="ISO 10218">10218</a></li> <li><a href="/wiki/Full_BASIC" title="Full BASIC">10279</a></li> <li><a href="/wiki/ISO_10303" title="ISO 10303">10303</a> <ul><li><a href="/wiki/EXPRESS_(data_modeling_language)" title="EXPRESS (data modeling language)">-11</a></li> <li><a href="/wiki/ISO_10303-21" title="ISO 10303-21">-21</a></li> <li><a href="/wiki/ISO_10303-22" title="ISO 10303-22">-22</a></li> <li><a href="/wiki/ISO_10303-28" title="ISO 10303-28">-28</a></li> <li><a href="/wiki/STEP-NC" title="STEP-NC">-238</a></li></ul></li> <li><a href="/wiki/Market_Identifier_Code" title="Market Identifier Code">10383</a></li> <li><a href="/wiki/ArmSCII" title="ArmSCII">10585</a></li> <li><a href="/wiki/IS-IS" title="IS-IS">10589</a></li> <li><a href="/wiki/ISO_10628" title="ISO 10628">10628</a></li> <li><a href="/wiki/Universal_Coded_Character_Set" title="Universal Coded Character Set">10646</a></li> <li><a href="/wiki/Torx" title="Torx">10664</a></li> <li><a href="/wiki/RM-ODP" title="RM-ODP">10746</a></li> <li><a href="/wiki/Multibus" title="Multibus">10861</a></li> <li><a href="/wiki/International_Standard_Music_Number" title="International Standard Music Number">10957</a></li> <li><a href="/wiki/ISO_10962" title="ISO 10962">10962</a></li> <li><a href="/wiki/ISO/IEC_10967" title="ISO/IEC 10967">10967</a></li> <li><a href="/wiki/ISO/IEEE_11073" title="ISO/IEEE 11073">11073</a></li> <li><a href="/wiki/ISO_11170" title="ISO 11170">11170</a></li> <li><a href="/wiki/MPEG-1" title="MPEG-1">11172</a></li> <li><a href="/wiki/ISO/IEC_11179" title="ISO/IEC 11179">11179</a></li> <li><a href="/wiki/ISO/IEC_11404" title="ISO/IEC 11404">11404</a></li> <li><a href="/wiki/JBIG" title="JBIG">11544</a></li> <li><a href="/wiki/ISO_11783" title="ISO 11783">11783</a></li> <li><a href="/wiki/ISO_11784_and_ISO_11785" title="ISO 11784 and ISO 11785">11784</a></li> <li><a href="/wiki/ISO_11784_and_ISO_11785" title="ISO 11784 and ISO 11785">11785</a></li> <li><a href="/wiki/ISO/IEC_11801" title="ISO/IEC 11801">11801</a></li> <li><a href="/wiki/Trusted_Platform_Module" title="Trusted Platform Module">11889</a></li> <li><a href="/wiki/CAN_bus#CAN_lower-layer_standards" title="CAN bus">11898</a></li> <li><a href="/wiki/ISO_11940" title="ISO 11940">11940</a> (<a href="/wiki/ISO_11940-2" title="ISO 11940-2">-2</a>)</li> <li><a href="/wiki/ISO/TR_11941" title="ISO/TR 11941">11941</a></li> <li><a href="/wiki/ISO/TR_11941" title="ISO/TR 11941">11941 (TR)</a></li> <li><a href="/wiki/ISO_11992" title="ISO 11992">11992</a></li> <li><a href="/wiki/ISO_12006" title="ISO 12006">12006</a></li> <li><a href="/wiki/DICOM" title="DICOM">12052</a></li> <li><a href="/wiki/ISO/IEC_TR_12182" title="ISO/IEC TR 12182">12182</a></li> <li><a href="/wiki/ISO/IEC_12207" title="ISO/IEC 12207">12207</a></li> <li><a href="/wiki/TIFF/EP" title="TIFF/EP">12234-2</a></li> <li><a href="/wiki/Linguistic_categories#ISO_12620_(ISO_TC37_Data_Category_Registry,_ISOcat)" title="Linguistic categories">12620</a></li> <li><a href="/wiki/Prolog" title="Prolog">13211</a> <ul><li><a href="/wiki/Prolog" title="Prolog">-1</a></li> <li><a href="/wiki/Prolog" title="Prolog">-2</a></li></ul></li> <li><a href="/wiki/Isofix" title="Isofix">13216</a></li> <li><a href="/wiki/Topic_map" title="Topic map">13250</a></li> <li><a href="/wiki/ISO_13399" title="ISO 13399">13399</a></li> <li><a href="/wiki/ISO_13406-2" title="ISO 13406-2">13406-2</a></li> <li><a href="/wiki/110_film" title="110 film">13450</a></li> <li><a href="/wiki/ISO_13485" title="ISO 13485">13485</a></li> <li><a href="/wiki/ISO_13490" title="ISO 13490">13490</a></li> <li><a href="/wiki/ISO_13567" title="ISO 13567">13567</a></li> <li><a href="/wiki/Z_notation" title="Z notation">13568</a></li> <li><a href="/wiki/ISO_13584" title="ISO 13584">13584</a></li> <li><a href="/wiki/International_Bank_Account_Number" title="International Bank Account Number">13616</a></li> <li><a href="/wiki/ISLISP" title="ISLISP">13816</a></li> <li><a href="/wiki/MPEG-2" title="MPEG-2">13818</a></li> <li><a href="/wiki/ISO_14000" class="mw-redirect" title="ISO 14000">14000</a></li> <li><a href="/wiki/ISO_14031" title="ISO 14031">14031</a></li> <li><a href="/wiki/ISO_14224" title="ISO 14224">14224</a></li> <li><a href="/wiki/PDF/UA" title="PDF/UA">14289</a></li> <li><a href="/wiki/Horsepower" title="Horsepower">14396</a></li> <li><a href="/wiki/ISO/IEC_14443" title="ISO/IEC 14443">14443</a></li> <li><a href="/wiki/MPEG-4" title="MPEG-4">14496</a> <ul><li><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">-2</a></li> <li><a href="/wiki/MPEG-4_Part_3" title="MPEG-4 Part 3">-3</a></li> <li><a href="/wiki/Delivery_Multimedia_Integration_Framework" title="Delivery Multimedia Integration Framework">-6</a></li> <li><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">-10</a></li> <li><a href="/wiki/MPEG-4_Part_11" title="MPEG-4 Part 11">-11</a></li> <li><a href="/wiki/ISO_base_media_file_format" title="ISO base media file format">-12</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-14</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-17</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-20</a></li></ul></li> <li><a href="/wiki/ISO_14617" title="ISO 14617">14617</a></li> <li><a href="/wiki/ISO_14644" title="ISO 14644">14644</a></li> <li><a href="/wiki/STEP-NC" title="STEP-NC">14649</a></li> <li><a href="/wiki/ISO/IEC_14651" title="ISO/IEC 14651">14651</a></li> <li><a href="/wiki/ISO_14698" title="ISO 14698">14698</a></li> <li><a href="/wiki/Software_maintenance" title="Software maintenance">14764</a></li> <li><a href="/wiki/C%2B%2B" title="C++">14882</a></li> <li><a href="/wiki/ISO_14971" title="ISO 14971">14971</a></li> <li><a href="/wiki/ISO_15022" title="ISO 15022">15022</a></li> <li><a href="/wiki/ISO_15189" title="ISO 15189">15189</a></li> <li><a href="/wiki/ISO/IEC_15288" title="ISO/IEC 15288">15288</a></li> <li><a href="/wiki/Ada_Semantic_Interface_Specification" title="Ada Semantic Interface Specification">15291</a></li> <li><a href="/wiki/ISO_15398" title="ISO 15398">15398</a></li> <li><a href="/wiki/Common_Criteria" title="Common Criteria">15408</a></li> <li><a href="/wiki/JPEG_2000" title="JPEG 2000">15444</a> <ul><li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">-3</a></li> <li><a href="/wiki/JPIP" title="JPIP">-9</a></li></ul></li> <li><a href="/wiki/HTML" title="HTML">15445</a></li> <li><a href="/wiki/PDF417" title="PDF417">15438</a></li> <li><a href="/wiki/ISO/IEC_15504" title="ISO/IEC 15504">15504</a></li> <li><a href="/wiki/International_Standard_Identifier_for_Libraries_and_Related_Organizations" title="International Standard Identifier for Libraries and Related Organizations">15511</a></li> <li><a href="/wiki/ISO_15686" title="ISO 15686">15686</a></li> <li><a href="/wiki/ISO/IEC_15693" title="ISO/IEC 15693">15693</a></li> <li><a href="/wiki/International_Standard_Audiovisual_Number" title="International Standard Audiovisual Number">15706</a> <ul><li><a href="/wiki/International_Standard_Audiovisual_Number" title="International Standard Audiovisual Number">-2</a></li></ul></li> <li><a href="/wiki/International_Standard_Musical_Work_Code" title="International Standard Musical Work Code">15707</a></li> <li><a href="/wiki/ISO/IEC_15897" title="ISO/IEC 15897">15897</a></li> <li><a href="/wiki/ISO_15919" title="ISO 15919">15919</a></li> <li><a href="/wiki/ISO_15924" title="ISO 15924">15924</a></li> <li><a href="/wiki/ISO_15926" title="ISO 15926">15926</a></li> <li><a href="/wiki/ISO_15926_WIP" title="ISO 15926 WIP">15926 WIP</a></li> <li><a href="/wiki/PDF/X" title="PDF/X">15930</a></li> <li><a href="/wiki/MPEG-7" title="MPEG-7">15938</a></li> <li><a href="/wiki/MaxiCode" title="MaxiCode">16023</a></li> <li><a href="/wiki/ECMAScript" title="ECMAScript">16262</a></li> <li><a href="/wiki/Quality_function_deployment" title="Quality function deployment">16355-1</a></li> <li><a href="/wiki/Mixed_raster_content" title="Mixed raster content">16485</a></li> <li><a href="/wiki/PDF/VT" title="PDF/VT">16612-2</a></li> <li><a href="/wiki/ISO_16750" title="ISO 16750">16750</a></li> <li><a href="/wiki/IATF_16949" title="IATF 16949">16949 (TS)</a></li> <li><a href="/wiki/ISO/IEC_17024" title="ISO/IEC 17024">17024</a></li> <li><a href="/wiki/ISO/IEC_17025" title="ISO/IEC 17025">17025</a></li> <li><a href="/wiki/ISO_17100" title="ISO 17100">17100</a></li> <li><a href="/wiki/Open_Virtualization_Format" title="Open Virtualization Format">17203</a></li> <li><a href="/wiki/SDMX" title="SDMX">17369</a></li> <li><a href="/wiki/Legal_Entity_Identifier" title="Legal Entity Identifier">17442</a></li> <li><a href="/wiki/COLLADA" title="COLLADA">17506</a></li> <li><a href="/wiki/ISO/IEC_27002" title="ISO/IEC 27002">17799</a></li> <li><a href="/wiki/QR_code" title="QR code">18004</a></li> <li><a href="/wiki/ISO/IEC_18014" title="ISO/IEC 18014">18014</a></li> <li><a href="/wiki/JPEG_XL" title="JPEG XL">18181</a></li> <li><a href="/wiki/ISO_18245" title="ISO 18245">18245</a></li> <li><a href="/wiki/Process_Specification_Language" title="Process Specification Language">18629</a></li> <li><a href="/wiki/Photographic_Activity_Test" title="Photographic Activity Test">18916</a></li> <li><a href="/wiki/PDF/A" title="PDF/A">19005</a></li> <li><a href="/wiki/ISO_19011" title="ISO 19011">19011</a></li> <li><a href="/wiki/ISO_19092-1" class="mw-redirect" title="ISO 19092-1">19092</a> <ul><li><a href="/wiki/ISO_19092-1" class="mw-redirect" title="ISO 19092-1">-1</a></li> <li><a href="/wiki/ISO_19092-2" class="mw-redirect" title="ISO 19092-2">-2</a></li></ul></li> <li><a href="/wiki/ISO_19114" title="ISO 19114">19114</a></li> <li><a href="/wiki/Geospatial_metadata#ISO_19115:_Geographic_information_–_Metadata" title="Geospatial metadata">19115</a></li> <li><a href="/wiki/Simple_Features" title="Simple Features">19125</a></li> <li><a href="/wiki/Geography_Markup_Language#ISO_19136" title="Geography Markup Language">19136</a></li> <li><a href="/wiki/Shoe_size" title="Shoe size">19407</a></li> <li><a href="/wiki/ISO_19439" title="ISO 19439">19439</a></li> <li><a href="/wiki/Common_Object_Request_Broker_Architecture" title="Common Object Request Broker Architecture">19500</a></li> <li><a href="/wiki/Unified_Modeling_Language" title="Unified Modeling Language">19501</a></li> <li><a href="/wiki/Meta-Object_Facility" title="Meta-Object Facility">19502</a></li> <li><a href="/wiki/XML_Metadata_Interchange" title="XML Metadata Interchange">19503</a></li> <li><a href="/wiki/Unified_Modeling_Language" title="Unified Modeling Language">19505</a></li> <li><a href="/wiki/Knowledge_Discovery_Metamodel" title="Knowledge Discovery Metamodel">19506</a></li> <li><a href="/wiki/Object_Constraint_Language" title="Object Constraint Language">19507</a></li> <li><a href="/wiki/Meta-Object_Facility" title="Meta-Object Facility">19508</a></li> <li><a href="/wiki/XML_Metadata_Interchange" title="XML Metadata Interchange">19509</a></li> <li><a href="/wiki/Business_Process_Model_and_Notation" title="Business Process Model and Notation">19510</a></li> <li><a href="/wiki/ISO_19600" title="ISO 19600">19600</a></li> <li><a href="/wiki/ISO/IEC_19752" title="ISO/IEC 19752">19752</a></li> <li><a href="/wiki/RELAX_NG" title="RELAX NG">19757</a></li> <li><a href="/wiki/ISO/IEC_19770" title="ISO/IEC 19770">19770</a></li> <li><a href="/wiki/X3D" title="X3D">19775-1</a></li> <li><a href="/wiki/ISO/IEC_19794-5" title="ISO/IEC 19794-5">19794-5</a></li> <li><a href="/wiki/Cloud_Infrastructure_Management_Interface" title="Cloud Infrastructure Management Interface">19831</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">20000–29999</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO/IEC_20000" title="ISO/IEC 20000">20000</a></li> <li><a href="/wiki/ISO_20022" title="ISO 20022">20022</a></li> <li><a href="/wiki/ISO_20121" title="ISO 20121">20121</a></li> <li><a href="/wiki/ISO_20400" title="ISO 20400">20400</a></li> <li><a href="/wiki/Open_Data_Protocol" title="Open Data Protocol">20802</a></li> <li><a href="/wiki/Han_Xin_code" title="Han Xin code">20830</a></li> <li><a href="/wiki/MPEG-21" title="MPEG-21">21000</a></li> <li><a href="/wiki/ISO_21001" title="ISO 21001">21001</a></li> <li><a href="/wiki/International_Standard_Text_Code" title="International Standard Text Code">21047</a></li> <li><a href="/wiki/JPEG_XS" title="JPEG XS">21122</a></li> <li><a href="/wiki/ISO_21500" title="ISO 21500">21500</a></li> <li><a href="/wiki/ISO/IEC_21827" title="ISO/IEC 21827">21827</a></li> <li><a href="/wiki/ISO_22000" title="ISO 22000">22000</a></li> <li><a href="/wiki/ECMAScript" title="ECMAScript">22275</a></li> <li><a href="/wiki/ISO_22300" title="ISO 22300">22300</a></li> <li><a href="/wiki/ISO_22301" title="ISO 22301">22301</a></li> <li><a href="/wiki/ISO_22395" title="ISO 22395">22395</a></li> <li><a href="/wiki/ECMAScript_for_XML" title="ECMAScript for XML">22537</a></li> <li><a href="/wiki/MPEG-A" title="MPEG-A">23000</a></li> <li><a href="/wiki/MPEG-D" title="MPEG-D">23003</a></li> <li><a href="/wiki/MPEG-H" title="MPEG-H">23008</a></li> <li><a href="/wiki/Dynamic_Adaptive_Streaming_over_HTTP" title="Dynamic Adaptive Streaming over HTTP">23009</a></li> <li><a href="/wiki/Versatile_Video_Coding" title="Versatile Video Coding">23090-3</a></li> <li><a href="/wiki/MPEG-G" title="MPEG-G">23092</a></li> <li><a href="/wiki/Essential_Video_Coding" title="Essential Video Coding">23094-1</a></li> <li><a href="/wiki/LCEVC" title="LCEVC">23094-2</a></li> <li><a href="/wiki/C_Sharp_(programming_language)" title="C Sharp (programming language)">23270</a></li> <li><a href="/wiki/Common_Language_Infrastructure" title="Common Language Infrastructure">23271</a></li> <li><a href="/wiki/Linux_Standard_Base" title="Linux Standard Base">23360</a></li> <li><a href="/wiki/Rectangular_Micro_QR_Code" title="Rectangular Micro QR Code">23941</a></li> <li><a href="/wiki/PDF/E" title="PDF/E">24517</a></li> <li><a href="/wiki/Lexical_Markup_Framework" title="Lexical Markup Framework">24613</a></li> <li><a href="/wiki/ISO-TimeML" title="ISO-TimeML">24617</a></li> <li><a href="/wiki/Common_Logic" title="Common Logic">24707</a></li> <li><a href="/wiki/MicroPDF417" title="MicroPDF417">24728</a></li> <li><a href="/wiki/ISO_25178" title="ISO 25178">25178</a></li> <li><a href="/wiki/ISO_25964" title="ISO 25964">25964</a></li> <li><a href="/wiki/ISO_26000" title="ISO 26000">26000</a></li> <li><a href="/wiki/ISO_26262" title="ISO 26262">26262</a></li> <li><a href="/wiki/OpenDocument" title="OpenDocument">26300</a></li> <li><a href="/wiki/Digital_object_identifier" title="Digital object identifier">26324</a></li> <li><a href="/wiki/ISO/IEC_27000-series" class="mw-redirect" title="ISO/IEC 27000-series">27000 series</a></li> <li><a href="/wiki/ISO/IEC_27000" title="ISO/IEC 27000">27000</a></li> <li><a href="/wiki/ISO/IEC_27001" title="ISO/IEC 27001">27001</a></li> <li><a href="/wiki/ISO/IEC_27002" title="ISO/IEC 27002">27002</a></li> <li><a href="/wiki/ISO/IEC_27005" title="ISO/IEC 27005">27005</a></li> <li><a href="/wiki/ISO/IEC_27006" title="ISO/IEC 27006">27006</a></li> <li><a href="/wiki/International_Standard_Name_Identifier" title="International Standard Name Identifier">27729</a></li> <li><a href="/wiki/ISO_28000" title="ISO 28000">28000</a></li> <li>29110</li> <li><a href="/wiki/Requirements_engineering" title="Requirements engineering">29148</a></li> <li><a href="/wiki/JPEG_XR" title="JPEG XR">29199-2</a></li> <li><a href="/wiki/Office_Open_XML" title="Office Open XML">29500</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">30000+</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ruby_(programming_language)" title="Ruby (programming language)">30170</a></li> <li><a href="/wiki/ISO_31000" title="ISO 31000">31000</a></li> <li><a href="/wiki/PDF" title="PDF">32000</a></li> <li><a href="/wiki/ISO_37001" title="ISO 37001">37001</a></li> <li><a href="/wiki/ISO/IEC_38500" title="ISO/IEC 38500">38500</a></li> <li><a href="/wiki/Graph_Query_Language" title="Graph Query Language">39075</a></li> <li><a href="/wiki/Web_Content_Accessibility_Guidelines" title="Web Content Accessibility Guidelines">40500</a></li> <li><a href="/wiki/ISO/IEC_42010" title="ISO/IEC 42010">42010</a></li> <li><a href="/wiki/ISO_45001" title="ISO 45001">45001</a></li> <li><a href="/wiki/ISO_50001" title="ISO 50001">50001</a></li> <li><a href="/wiki/ISO_55000" title="ISO 55000">55000</a></li> <li><a href="/wiki/ISO_56000" title="ISO 56000">56000</a></li> <li><a href="/wiki/ISO/IEC_80000" title="ISO/IEC 80000">80000</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:ISO_standards" title="Category:ISO standards">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style></div><div role="navigation" class="navbox" aria-labelledby="Acoustics" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist 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<li><a href="/wiki/Monochord" title="Monochord">Monochord</a></li> <li><a href="/wiki/Reverberation" title="Reverberation">Reverberation</a></li> <li><a href="/wiki/Soundproofing" title="Soundproofing">Soundproofing</a></li> <li><a href="/wiki/String_vibration" title="String vibration">String vibration</a></li> <li><a href="/wiki/Sympathetic_resonance" title="Sympathetic resonance">Sympathetic resonance</a></li></ul> </div></td><td class="noviewer navbox-image" rowspan="5" style="width:1px;padding:0 0 0 2px"><div><div class="plainlist"><ul><li><span typeof="mw:File"><a href="/wiki/File:Spectrogram_showing_shared_partials.png" class="mw-file-description"><img alt="A spectrogram of a violin playing a note and then a perfect fifth above it. The shared partials are highlighted by the white dashes." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/80px-Spectrogram_showing_shared_partials.png" decoding="async" width="80" height="67" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/120px-Spectrogram_showing_shared_partials.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/26/Spectrogram_showing_shared_partials.png/160px-Spectrogram_showing_shared_partials.png 2x" data-file-width="300" data-file-height="250" /></a></span></li><li><span style="font-size:85%;"><a href="/wiki/Spectrogram" title="Spectrogram">Spectrogram</a></span></li></ul></div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Psychoacoustics" title="Psychoacoustics">Psychoacoustics</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Pitch_(music)" title="Pitch (music)">Pitch</a> <ul><li><a href="/wiki/Bark_scale" title="Bark scale">Bark scale</a></li> <li><a href="/wiki/Mel_scale" title="Mel scale">Mel scale</a></li></ul></li> <li><a class="mw-selflink selflink">Equal-loudness contour</a> <ul><li><a href="/wiki/Fletcher%E2%80%93Munson_curves" class="mw-redirect" title="Fletcher–Munson curves">Fletcher–Munson curves</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Audio_frequency" title="Audio frequency">Audio frequency</a> and <a href="/wiki/Pitch_(music)" title="Pitch (music)">pitch</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beat_(acoustics)" title="Beat (acoustics)">Beat</a></li> <li><a href="/wiki/Formant" title="Formant">Formant</a></li> <li><a href="/wiki/Fundamental_frequency" title="Fundamental frequency">Fundamental frequency</a></li> <li><a href="/wiki/Frequency_spectrum" class="mw-redirect" title="Frequency spectrum">Frequency spectrum</a> <ul><li><a href="/wiki/Harmonic_spectrum" title="Harmonic spectrum">harmonic spectrum</a></li></ul></li> <li><a href="/wiki/Harmonic" title="Harmonic">Harmonic</a> <ul><li><a href="/wiki/Harmonic_series_(music)" title="Harmonic series (music)">Series</a></li> <li><a href="/wiki/Inharmonicity" title="Inharmonicity">Inharmonicity</a></li> <li><a href="/wiki/Missing_fundamental" title="Missing fundamental">Missing fundamental</a></li></ul></li> <li><a href="/wiki/Combination_tone" title="Combination tone">Combination tone</a></li> <li><a href="/wiki/Mersenne%27s_laws" title="Mersenne's laws">Mersenne's laws</a></li> <li><a href="/wiki/Overtone" title="Overtone">Overtone</a></li> <li><a href="/wiki/Acoustic_resonance" title="Acoustic resonance">Resonance</a></li> <li><a href="/wiki/Standing_wave" title="Standing wave">Standing wave</a> <ul><li><a href="/wiki/Node_(physics)" title="Node (physics)">Node</a></li></ul></li> <li><a href="/wiki/Undertone_series" title="Undertone series">Subharmonic</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Acousticians</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/John_Backus_(acoustician)" title="John Backus (acoustician)">John Backus</a></li> <li><a href="/wiki/Jens_Blauert" title="Jens Blauert">Jens Blauert</a></li> <li><a href="/wiki/Ernst_Chladni" title="Ernst Chladni">Ernst Chladni</a></li> <li><a href="/wiki/Hermann_von_Helmholtz" title="Hermann von Helmholtz">Hermann von Helmholtz</a></li> <li><a href="/wiki/Carleen_Hutchins" title="Carleen Hutchins">Carleen Hutchins</a></li> <li><a href="/wiki/Franz_Melde" title="Franz Melde">Franz Melde</a></li> <li><a href="/wiki/Marin_Mersenne" title="Marin Mersenne">Marin Mersenne</a></li> <li><a href="/wiki/Werner_Meyer-Eppler" title="Werner Meyer-Eppler">Werner Meyer-Eppler</a></li> <li><a href="/wiki/John_William_Strutt,_3rd_Baron_Rayleigh" title="John William Strutt, 3rd Baron Rayleigh">Lord Rayleigh</a></li> <li><a href="/wiki/Joseph_Sauveur" title="Joseph Sauveur">Joseph Sauveur</a></li> <li><a href="/wiki/D._Van_Holliday" title="D. Van Holliday">D. Van Holliday</a></li> <li><a href="/wiki/Thomas_Young_(scientist)" title="Thomas Young (scientist)">Thomas Young</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related topics</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Echo" title="Echo">Echo</a></li> <li><a href="/wiki/Infrasound" title="Infrasound">Infrasound</a></li> <li><a href="/wiki/Sound" title="Sound">Sound</a></li> <li><a href="/wiki/Ultrasound" title="Ultrasound">Ultrasound</a></li> <li><a href="/wiki/Musical_acoustics" title="Musical acoustics">Musical acoustics</a> <ul><li><a href="/wiki/Piano_acoustics" title="Piano acoustics">Piano</a></li> <li><a href="/wiki/Violin_acoustics" title="Violin acoustics">Violin</a></li></ul></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="3"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Acoustics" title="Category:Acoustics">Category</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; 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