{"id":18010,"date":"2023-09-26T09:27:22","date_gmt":"2023-09-26T07:27:22","guid":{"rendered":"https:\/\/mag.ebmpapst.com\/en\/?p=18010"},"modified":"2025-02-28T13:01:56","modified_gmt":"2025-02-28T12:01:56","slug":"the-formula-for-psychoacoustic-quality","status":"publish","type":"post","link":"https:\/\/mag.ebmpapst.com\/en\/industries\/heating\/the-formula-for-psychoacoustic-quality_18010\/","title":{"rendered":"The formula for psychoa\u00adcoustic quality"},"content":{"rendered":"<div class=\"wp-block-image\">\n<figure class=\"alignright size-full is-resized\"><img decoding=\"async\" src=\"https:\/\/ebmpapst-7237.kxcdn.com\/de\/files\/2023\/09\/ebm-papst_formeln-sind-sexy_psychoakustik_marc-schneider.jpg\" alt class=\"wp-image-29416\" style=\"width:267px;height:600px\"><figcaption class=\"wp-element-caption\">Dr. Marc Schneider is respon\u00adsible for Pre-Devel\u00adop\u00adment Aeroa\u00adcoustics at ebm-papst. (Photo | ebm-papst)<\/figcaption><\/figure>\n<\/div>\n\n\n<p>Direc\u00adtives, such as \u201cTech\u00adnical Instruc\u00adtions for Protec\u00adtion against Noise 6.1\u201d in Germany, regu\u00adlate how loud a heat pump is allowed to be. In a resi\u00adden\u00adtial area, for example, it can operate at 40 dB (A) at night. These are strict limits and the following applies as a basic prin\u00adciple: the fewer deci\u00adbels, the less trouble is caused with the neigh\u00adbors. But there are other factors that make all the differ\u00adence in the end. In stan\u00addard\u00adized exper\u00adi\u00adments, psychoa\u00adcoustics inves\u00adti\u00adgates how pleasant different people find a noise and trans\u00adlates this into objec\u00adtively measur\u00adable values. The final value we are talking about here is the psychoa\u00adcoustic overall quality of a sound, Q<sub>OA<\/sub>. The higher the Q<sub>OA<\/sub>, the more pleasant the noise is to human ears. ebm-papst main\u00adtains its own psychoa\u00adcoustics labo\u00adra\u00adtory and has tested various compo\u00adsi\u00adtions of heat pump noises on over 100 subjects. <\/p>\n\n\n\n<p>Four para\u00adme\u00adters are rele\u00advant for the Q<sub>OA<\/sub> in this context: <em><strong>N<\/strong><\/em> is the loud\u00adness, measured in the unit sone. It indi\u00adcates how loud a noise is for human hearing. <em><strong>S<\/strong><\/em> is the sharp\u00adness, measured in the unit acum. It indi\u00adcates how many high frequen\u00adcies a noise contains. <em><strong>T<\/strong><\/em> is the tonality, measured in the unit tuHMS. It indi\u00adcates how disrup\u00adtive indi\u00advidual tones in a noise are perceived as being. <em><strong>H<\/strong><\/em> is the Shannon entropy, measured in bits. It indi\u00adcates how much a noise changes over time and how randomly this happens, e.g. swelling and subsiding.<\/p>\n\n\n\n<h2 class=\"wp-block-heading no-clear\">Happy neigh\u00adbors thanks to quiet heat pump<\/h2>\n\n\n\n<p>From the hearing tests, it is then possible to deter\u00admine the pref\u00ader\u00adences and incli\u00adna\u00adtions of the subjects and to weight them statis\u00adti\u00adcally. The statis\u00adtical calcu\u00adla\u00adtions give a value to the prelim\u00adi\u00adnary factors k1, k2, k3 and k4. k0 is merely a quality constant, which defines the Q<sub>OA<\/sub> so that a value of Q<sub>OA<\/sub> = 0 corre\u00adsponds to a volume hazardous to health. <\/p>\n\n\n<div class=\"wp-block-image\">\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;69e58c75cb40f&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"69e58c75cb40f\" class=\"alignleft size-full is-resized wp-lightbox-container\"><img loading=\"lazy\" decoding=\"async\" width=\"660\" height=\"460\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/09\/ebm-papst_psychoakustik_formel_schaubild_EN.jpg\" alt class=\"wp-image-18043\" style=\"width:300px;height:undefinedpx\" srcset=\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/09\/ebm-papst_psychoakustik_formel_schaubild_EN.jpg 660w, https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/09\/ebm-papst_psychoakustik_formel_schaubild_EN-260x181.jpg 260w, https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/09\/ebm-papst_psychoakustik_formel_schaubild_EN-450x314.jpg 450w, https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/09\/ebm-papst_psychoakustik_formel_schaubild_EN-300x209.jpg 300w\" sizes=\"auto, (max-width: 660px) 100vw, 660px\"><button class=\"lightbox-trigger\" type=\"button\" aria-haspopup=\"dialog\" aria-label=\"Enlarge\" data-wp-init=\"callbacks.initTriggerButton\" data-wp-on--click=\"actions.showLightbox\" data-wp-style--right=\"state.imageButtonRight\" data-wp-style--top=\"state.imageButtonTop\">\n\t\t\t<svg width=\"12\" height=\"12\" fill=\"none\" viewBox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><figcaption class=\"wp-element-caption\">If the psychoa\u00adcoustic quality Q (y-axis) of a noise increases by the value 2 (green compared to the red curve), the sound may also be a whole 8 dB (A) louder (x-axis), and is never\u00adthe\u00adless perceived as equally pleasant or equally as disrup\u00adtive. Put in a different way: the higher Q is, the more pleasant and quieter the noise is perceived by humans. (Graphic | ebm-papst)<\/figcaption><\/figure>\n<\/div>\n\n\n<p>The values obtained exper\u00adi\u00admen\u00adtally and statis\u00adti\u00adcally for the prelim\u00adi\u00adnary factors can be referred to phys\u00adical, i.e. objec\u00adtively measur\u00adable, para\u00adme\u00adters \u2013 and so finally to the design of a heat pump and the fans installed in it. The usual starting points for noise reduc\u00adtion include air duct design, turbu\u00adlence or inflows at the fan. The tests show that, if we improve the Q<sub>OA<\/sub> of a specific heat pump noise by the value 2 at a constant noise level, it is perceived as being as pleasant as having made it quieter by a total of 8 db (A)! <\/p>\n\n\n\n<p>That is why a high Q<sub>OA<\/sub> means a nicer time spent in your own garden, and a better rela\u00adtion\u00adship with the neigh\u00adbors.<\/p>\n\n\n\n<div style=\"height:15px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Read more about heat pumps:<\/h2>\n\n\n\n<a href=\"https:\/\/www.ebmpapst.com\/de\/en\/industries\/heating-technology\/heat-pumps.html\" target=\"blank\" class=\"product-link\">\n\t<i class=\"icon-next\" aria-hidden=\"true\"><\/i>\n\t<h4>Sustain\u00adable energy supply with heat pumps<\/h4>\n\t<p>ebm-papst offers effi\u00adcient and quiet prod\u00aducts suit\u00adable for indoor, outdoor or hybrid heat pump appli\u00adca\u00adtions.<\/p>\n\t<div class=\"imgdiv\" style=\"background-image:url('https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2023\/07\/warmepumpe_ebm-papst_produktlink_600-600.jpg');\"><\/div>\n\t\n<\/a>\n\n","protected":false},"excerpt":{"rendered":"<p>Direc\u00adtives, such as \u201cTech\u00adnical Instruc\u00adtions for Protec\u00adtion against Noise 6.1\u201d in Germany, regu\u00adlate how loud a heat pump is allowed to be. In a resi\u00adden\u00adtial area, for example, it can operate at 40 dB (A) at night. These are strict limits and the following applies as a basic prin\u00adciple: the fewer deci\u00adbels, the less trouble [\u2026]<\/p>\n","protected":false},"author":36,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[16,8,9],"tags":[],"class_list":["post-18010","post","type-post","status-publish","format-standard","hentry","category-fans","category-heating","category-refrigeration-ventilation"],"acf":[],"_links":{"self":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/18010","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/users\/36"}],"replies":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/comments?post=18010"}],"version-history":[{"count":25,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/18010\/revisions"}],"predecessor-version":[{"id":21258,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/18010\/revisions\/21258"}],"wp:attachment":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/media?parent=18010"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/categories?post=18010"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/tags?post=18010"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}