{"id":6962,"date":"2026-05-08T12:42:49","date_gmt":"2026-05-08T12:42:49","guid":{"rendered":"https:\/\/www.airvision.be\/?p=6962"},"modified":"2026-05-08T12:42:30","modified_gmt":"2026-05-08T12:42:30","slug":"pitfalls-2-multi-machine-acoustics","status":"publish","type":"post","link":"https:\/\/www.airvision.be\/en\/pitfalls-2-multi-machine-acoustics\/","title":{"rendered":"Pitfalls #2 &#8211; Multi-Machine &amp; Acoustics"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"266\" src=\"https:\/\/www.airvision.be\/wp-content\/uploads\/image-2-1024x266.png\" alt=\"\" class=\"wp-image-6957\" srcset=\"https:\/\/www.airvision.be\/wp-content\/uploads\/image-2-1024x266.png 1024w, https:\/\/www.airvision.be\/wp-content\/uploads\/image-2-300x78.png 300w, https:\/\/www.airvision.be\/wp-content\/uploads\/image-2-768x199.png 768w, https:\/\/www.airvision.be\/wp-content\/uploads\/image-2-1536x399.png 1536w, https:\/\/www.airvision.be\/wp-content\/uploads\/image-2.png 2002w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Multi-Machine Installations &amp; Acoustics: Beware of Cumulative Effects<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u201cBut each machine is rated at 85 dB(A)\u2026\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is a common comment when the overall noise level of an installation exceeds expectations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Individually, each fan complies with its specification \u2014 typically measured at 1 meter in free-field conditions.<br>Collectively, however, the installation may become too noisy.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Why?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Because in acoustics, sound levels do not add up linearly.<br>They combine logarithmically \u2014 and that makes a significant difference.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>The classic pitfall: comparing isolated values<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In multi-machine projects, the reasoning often goes like this:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Fan A: 85 dB(A) at 1 m<\/li>\n\n\n\n<li>Fan B: 85 dB(A) at 1 m<\/li>\n\n\n\n<li>Fan C: 85 dB(A) at 1 m<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The intuitive conclusion: we remain close to 85 dB(A).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In reality:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Two identical 85 dB(A) sources result in about 88 dB(A)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Three sources approach 90 dB(A)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Each additional source increases the overall sound level.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">And even this remains a simplified view\u2026<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Distance and environment make a major difference<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Published noise values are generally measured:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>At 1 meter<\/li>\n\n\n\n<li>In free-field conditions<\/li>\n\n\n\n<li>Without obstacles<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">In real installations:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Machines are positioned close to each other<\/li>\n\n\n\n<li>Walls reflect sound<\/li>\n\n\n\n<li>Ductwork transmits noise<\/li>\n\n\n\n<li>Steel structures can radiate vibration<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The surrounding environment can locally amplify sound levels far beyond theoretical values.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&#x1f449; In industrial acoustics, thinking per machine and relying solely on catalog values is a mistake.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Key takeaway<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In multi-machine configurations:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sound levels combine logarithmically<\/li>\n\n\n\n<li>Distance strongly affects perceived sound pressure<\/li>\n\n\n\n<li>The environment can significantly amplify the effect<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Most acoustic overruns are not caused by a \u201cnoisy fan,\u201d<br>but by the absence of a system-level analysis during the design phase.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Multi-Machine Installations &amp; Acoustics: Beware of Cumulative Effects \u201cBut each machine is rated at 85 dB(A)\u2026\u201d This is a common comment when the overall noise level of an installation exceeds [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":6963,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-6962","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technical-articles"],"_links":{"self":[{"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/posts\/6962","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/comments?post=6962"}],"version-history":[{"count":1,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/posts\/6962\/revisions"}],"predecessor-version":[{"id":6964,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/posts\/6962\/revisions\/6964"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/media\/6963"}],"wp:attachment":[{"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/media?parent=6962"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/categories?post=6962"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.airvision.be\/en\/wp-json\/wp\/v2\/tags?post=6962"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}