{"id":600,"date":"2010-09-16T16:20:10","date_gmt":"2010-09-16T06:20:10","guid":{"rendered":"http:\/\/blog.dbohs.com\/?p=600"},"modified":"2010-09-16T16:21:30","modified_gmt":"2010-09-16T06:21:30","slug":"calculating-laeq-from-a-series-of-decibels","status":"publish","type":"post","link":"https:\/\/blog.dbohs.com\/?p=600","title":{"rendered":"Calculating LAeq from a series of decibels"},"content":{"rendered":"

The equivalent sound pressure level L<\/strong>eq<\/strong><\/sub> <\/strong>for an eight hour day with a sound level varying as Lp<\/sub>(t).<\/em><\/p>\n

\"\"<\/a>
\n<\/em><\/p>\n

You rarely know Lp<\/sub>(t) \u2013 the pattern of noise exposure over the day, but sometimes the data is available, but a censored set of the data is used, perhaps just to look at the equivalent sound pressure level from a particular machine.<\/p>\n

For a series of noise measurements at regular intervals, the Leq<\/sub> can be calculated in Excel with the following \u201carray formula<\/strong>\u201d \u2013 a powerful but little known feature in Excel.<\/p>\n

=10*LOG10(AVERAGE(10^((your range<\/span>)\/10)))<\/p>\n

When the range \u2013 say the cells D1 and D2 are selected and the Shift+Control+Enter<\/strong> keys are pressed simultaneously, the formula bar in Excel will show the formula enclosed in {}<\/p>\n

\"\"<\/a><\/p>\n

If you just used the arithmetic average you would get 47.5, the wrong answer.<\/p>\n

If you try to use an Excel VAB macro with that formula, \u00a0it wont work as VBA does not have Log10() – you have to use Log(X)\/log(10).<\/p>\n","protected":false},"excerpt":{"rendered":"

How to calculate Leq with an array formula in Excel<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[94,20],"tags":[120,123,122,121],"class_list":["post-600","post","type-post","status-publish","format-standard","category-noise","category-occupational-hygiene","tag-excel","tag-leq","tag-macro","tag-vba","czr-hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t