CINXE.COM

<!doctype html> <html lang="en"> <head> <meta charset="UTF-8" > <link rel="stylesheet" type="text/css" href="static/css/www_1768595241320433331.css" > <title>Acoustics</title> <script type="application/ld+json"> { "@context":"https://schema.org", "@type":"Article", "headline":"Acoustics", "abstract":"Room acoustics and acoustic properties. decibel A, B and C calculations. Noise Rating (NR) curves. Sound transmission through walls. Calculate sound pressure, sound intensity and sound attenuation.", "url":"https://www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html", "image":["https://www.engineeringtoolbox.com/docs/documents/59/SoundDecibelABC.gif"], "datePublished":"2009-11-25T02:15:03Z", "dateModified":"2024-03-08T09:34:09Z", "author":[{ "@type":"Person", "name":"Editor Engineeringtoolbox", "url": "https://engineeringtoolbox.com" }] } </script> <link rel="preconnect" href="https://cdnjs.cloudflare.com" > <link rel="preconnect" href="https://pagead2.googlesyndication.com" > <link rel="preconnect" href="https://fundingchoicesmessages.google.com" > <link rel="dns-prefetch" href="https://cse.google.com" > <link rel="dns-prefetch" href="https://www.googletagmanager.com" > <link rel="dns-prefetch" href="https://googleads.g.doubleclick.net" > <link rel="dns-prefetch" href="https://clients1.google.com" > <link rel="dns-prefetch" href="https://fonts.googleapis.com" > <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"> </script> <meta name="robots" content="index,follow" > <meta name="apple-touch-fullscreen" content="YES" > <meta name="viewport" content="user-scalable=yes, width=device-width, initial-scale=1" > <meta name="keywords" content="acoustics decibel noise white machines control transducer audio sound level meters reduction environmental barrier measurement abatement absorbers software" > <meta name="description" content="Room acoustics and acoustic properties. decibel A, B and C calculations. Noise Rating (NR) curves. Sound transmission through walls. Calculate sound pressure, sound intensity and sound attenuation." >  <link rel="apple-touch-icon-precomposed" type="text/css" href="static/lib/img/apple-touch-icon.png" > <link rel="shortcut icon" type="image/x-icon" href="static/img/favicon.ico" > <script src="static/scripts/sgmlRender_93543702166710713.js" defer="defer"> </script> <script src="static/scripts/www_2004325036753648097.js" defer="defer"> </script> <link rel="amphtml" href="https://www.engineeringtoolbox.com/amp/acoustics-noise-decibels-t_27.html" > <link rel="canonical" href="https://www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html" >  <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= 'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-WH8MKZX');</script>  <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-3176996020956223" crossorigin="anonymous"></script> <script async src="https://fundingchoicesmessages.google.com/i/pub-3176996020956223?ers=1" nonce="kUwMyhBaatnOdZ-JwpEGCA"></script><script nonce="kUwMyhBaatnOdZ-JwpEGCA">(function() {function signalGooglefcPresent() {if (!window.frames['googlefcPresent']) {if (document.body) {const iframe = document.createElement('iframe'); iframe.style = 'width: 0; height: 0; border: none; z-index: -1000; left: -1000px; top: -1000px;'; iframe.style.display = 'none'; iframe.name = 'googlefcPresent'; document.body.appendChild(iframe);} else {setTimeout(signalGooglefcPresent, 0);}}}signalGooglefcPresent();})();</script> <script data-cfasync="false" type="text/javascript"> window.snigelPubConf = { "adengine": { "activeAdUnits": ["adhesive", "left1", "right", "top", "top2", "video", "incontent1", "incontent2"] } } </script> <script async data-cfasync="false" src="https://cdn.snigelweb.com/adengine/engineeringtoolbox.com/loader.js" type="text/javascript"></script> </head> <body> <div id="top"> <div id="logo"> <a href="https://www.engineeringtoolbox.com"> <img src="static/img/logo.jpg" width="350" height="60" alt="Engineering ToolBox" > </a> </div> <p id="intro" class="smallHide"> <a href="https://www.engineeringtoolbox.com"> Engineering ToolBox </a> - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!</p> <div id="adVideo" class="noPrint"> <div>  <div id="adngin-video-0"></div> </div> </div> </div> <div id="center"> <div id="gooSearch"> <script async src="https://cse.google.com/cse.js?cx=6a091aba9f3e1fba3"></script> <div class="gcse-searchbox-only"></div> </div> <div id="content"> <div> <h1> <a href="acoustics-noise-decibels-t_27.html"> Acoustics </a> </h1> <h2> Room acoustics and acoustic properties. decibel A, B and C calculations. Noise Rating (NR) curves. Sound transmission through walls. Calculate sound pressure, sound intensity and sound attenuation. </h2> <div id="adSlotTop1" class="noPrint"> <div>  <div id="adngin-top-0"></div> </div> </div> <h3> <a href="air-speed-sound-d_603.html" title="velocity speed sound air humidity temperature atmosphere pressure"> Air - Speed of Sound vs. Temperature </a> </h3> <p> Speed of sound in air at standard atmospheric pressure with temperatures ranging -40 to 1000 掳C (-40 to 1500 掳F) - Imperial and SI Units. </p> <h3> <a href="decibel-d_341.html" title="decibel db sound power intensity"> Decibel </a> </h3> <p> Logarithmic unit used to describe ratios of signal levels - like power or intensity - to a reference level. </p> <h3> <a href="decibel-d_59.html" title="decibel A B C debA debA debC"> Decibel A, B and C </a> </h3> <p> Sound pressure filters that compensates for the hearing sensed by the human ear. </p> <h3> <a href="fan-noise-d_61.html" title="fan sound noise level estimating"> Fans - Noise Power Generation </a> </h3> <p> The sound generated by a fan depends on the motor power, the volume capacity, the static pressure increase and the discharged volume. </p> <h3> <a href="floor-frequency-vibration-d_1641.html" title="floor vibration frequency "> Floor Vibrations </a> </h3> <p> Human activities like walking, running and dancing - and operating machines - can introduce floor vibrations due to resonance. </p> <h3> <a href="speed-sound-gases-d_1160.html" title="speed sound gases velocity"> Gases - Speed of Sound </a> </h3> <p> Speed of sound in some gases at zero degrees Celsius and atmospheric pressure. </p> <h3> <a href="sound-attenuation-ducts-d_75.html" title="acoustics sound attenuation rectangular lined ducts"> Lined Sheet-Metal Ducts - Sound Attenuation </a> </h3> <p> Noise attenuation in rectangular straight, lined, sheet metal ducts. </p> <h3> <a href="sound-speed-liquids-d_715.html" title="sound speed velocity fluids liquids"> Liquids - Speed of Sound </a> </h3> <p> Speed of sound in common fluids like water, glycerol, kerosene and more. </p> <div id="adSlotTop2" class="noPrint"> <div>  <div id="adngin-top2-0"></div> </div> </div> <h3> <a href="sound-pressure-d_66.html" title="sound pressure level room"> Maximum Sound Pressure Levels in Rooms </a> </h3> <p> Maximum recommended sound pressure levels in rooms like kindergartens, auditoriums, libraries, cinemas and more. </p> <h3> <a href="nc-noise-criterion-d_725.html" title="noise criterion nc"> NC - the Noise Criterion </a> </h3> <p> Noise Criterion - NC - level is a standard uesd to describe the relative loudness of a space within a range of frequencies. </p> <h3> <a href="decibel-dba-levels-d_728.html" title="leq decibel a level dba noise sound "> Noise - Acceptable dBA Level </a> </h3> <p> Acceptable noise - <i>dB<sub>A</sub></i> - level at typical common locations. </p> <h3> <a href="epa-protective-noise-level-d_720.html" title="epa noise level"> Noise - EPA Protective Levels </a> </h3> <p> The noise level should not exceed certain values to protect public health and welfare. </p> <h3> <a href="noise-exposure-level-d_718.html" title="noise exposure level dose period"> Noise - Maximum Daily Dose Level </a> </h3> <p> Maximum daily noise dose level when exposed to periods with different levels. </p> <h3> <a href="rel-noise-recommended-exposure-limit-d_716.html" title="noise recomended exposure limit REL"> Noise - Recommended Exposure Limits (REL) </a> </h3> <p> The NIOSH noise Recommended Exposure Limit - REL - for occupational noise </p> <h3> <a href="nc-noise-criterion-d_517.html" title="noice criterium NC sound"> Noise Criterion (NC) - Free Online Calculator </a> </h3> <p> Calculate Noise Criterion (NC) from octave band pressure levels. </p> <h3> <a href="noise-criteria-d_726.html" title="noise criterion rating dbA"> Noise Criterion vs. Noise Rating and dB(A) </a> </h3> <p> Comparing Noise Criterion (NC, NCB, RNC) to Noise Rating (NR) and dB(A). </p> <div id="adInContent1" class="noPrint"> <div>  <div id="adngin-incontent1-0"></div> </div> </div> <h3> <a href="noise-exposure-level-duration-d_717.html" title="noise exposure level duration "> Noise Exposure - Permissible Levels and Duration </a> </h3> <p> Exposure to noise should be controlled so that it is less than a maximum combination of exposure level and duration. </p> <h3> <a href="machines-sound-level-reduction-d_1411.html" title="machines sound noise reduction damping enclosures"> Noise from Machines - Enclosures and Sound Pressure Level Reductions </a> </h3> <p> Barriers and enclosures to reduce noise sound pressure levels from machines. </p> <h3> <a href="fan-blade-pass-frequency-d_1137.html" title="fan noise intensity blade pass frequency bpf"> Noise generated by Fans - Blade Pass Frequency (BPF) </a> </h3> <p> The<i>Blade Pass Frequency noise</i> generated by a fan can be very intense and varies with the number of blades and the rotation velocity. </p> <h3> <a href="road-traffic-noise-d_522.html" title="traffic noise roads cars"> Noise generated by Road Traffic </a> </h3> <p> Estimate noise level generated by traffic. </p> <h3> <a href="ducts-noise-generation-d_1405.html" title="noise sound generation duct speed volume air flow"> Noise generated in Air Ducts </a> </h3> <p> Estimate noise generated by air flow in ducts. </p> <h3> <a href="blade-dampers-noise-d_1291.html" title="blade dampers noise db pressure drop octave frequency"> Noise generated in Blade Dampers </a> </h3> <p> Sound power noise generated by blade dampers in ventilation systems. </p> <h3> <a href="nr-noise-rating-d_518.html" title="noise rating NR"> Noise Rating (NR) - Free Online Calculator </a> </h3> <p> An online Noise Rating (NR) calculator. </p> <h3> <a href="note-frequencies-d_520.html" title="note frequencies"> Notes, Octaves and Frequencies </a> </h3> <p> Frequencies vs. notes and octaves. </p> <div id="adInContent2" class="noPrint"> <div>  <div id="adngin-incontent2-0"></div> </div> </div> <h3> <a href="nr-noise-rating-d_60.html" title="acoustical noise sound rating NR curve diagram iso"> NR - the Noise Rating Curve </a> </h3> <p> The Noise Rating (NR) Curve used to determine acceptable indoor environments for hearing preservation, speech communication and annoyance. </p> <h3> <a href="octave-bands-frequency-limits-d_1602.html" title="octave bands frequency limits passband third 1/3 "> Octave Band Frequencies </a> </h3> <p> The octave and the 1/3 octave band frequencies. </p> <h3> <a href="outdoor-noise-d_62.html" title="outdoor sound noise level"> Outdoor Ambient Sound Pressure Levels </a> </h3> <p> Outdoor ambient sound pressure levels (dBA) in rural and urban business and industrial environments with or without limited traffic. </p> <h3> <a href="pnc-preferred-noise-criteria-d_727.html" title="preferred noise criterion"> PNC - the Preferred Noise Criterion </a> </h3> <p> A noise measurement system for continuous or ambient noise in indoor environments. </p> <h3> <a href="pnc-calculator-d_1150.html" title="pnc preferred noise criterion calculator "> Preferred Noise Criterion (PNC) - Calculator </a> </h3> <p> An online Preferred Noise Criterion (PNC) calculator. </p> <h3> <a href="outdoor-sound-partial-barriers-d_65.html" title="acoustic sound propagation transmittion reflection barriers"> Propagation of Outdoor Sound - Partial Barriers </a> </h3> <p> The transmission of outdoor sound through and around barriers - the Fresnel Number. </p> <h3> <a href="sound-propagation-indoor-d_72.html" title="sound acoustic propagating reverberant"> Propagation of Sound Indoors - the Room Constant </a> </h3> <p> In a room the sound or noise will reach the receiver as direct and reverberant sound. </p> <h3> <a href="outdoor-propagation-sound-d_64.html" title="outdoor propagation sound noise decibel pressure"> Propagation of Sound Outdoors - Attenuation vs. Distance </a> </h3> <p> The propagation of outdoors sound vs. distance and attenuation. </p> <h3> <a href="rc-room-criteria-d_729.html" title="room criteria"> RC - the Room Criteria </a> </h3> <p> The Room Criteria (RC) is used to measure background noise in buildings for frequencies ranging 16 to 4000 Hz. </p> <h3> <a href="voice-level-d_938.html" title="voice level distance noise sound decibel"> Required Voice Level at Distance </a> </h3> <p> Distance and perception of voice. </p> <h3> <a href="adding-decibel-d_63.html" title="sound decibel adding"> Signals - Adding Decibels </a> </h3> <p> The logarithmic decibel scale is convenient when adding signal values like sound power, pressure and others from two or more sources. </p> <h3> <a href="speech-interference-levels-d_1138.html" title="sil speech interference levels"> SIL - the Speech Interference Levels </a> </h3> <p> Background noise frequencies that interferes with speech. </p> <h3> <a href="sound-speed-solids-d_713.html" title="sound speed velocity solids"> Solids and Metals - Speed of Sound </a> </h3> <p> Speed of sound in solids and metals like aluminum, brass, concrete and more. </p> <h3> <a href="abatement-distance-source-d_723.html" title="sound noise abatement distance source pressure waves"> Sound - Abatement vs. the Distance from Source </a> </h3> <p> The disruption of the sound pressure wave and the reduction of noise is called attenuation - Sound Pressure Level vs. distance calculator. </p> <h3> <a href="air-speed-sound-attenuation-humidity-frequency-d_2161.html" title="air speed sound attenuation humidity frequency"> Sound - Attenuation and Speed vs. Sound Frequency and Air Humidity </a> </h3> <p> The speed and attenuation of sound in moist air varies with sound frequency and air humidity. </p> <h3> <a href="directivity-coefficient-sound-d_67.html" title="Acoustic sound direction coefficient"> Sound - Attenuation and the Directivity Coefficient </a> </h3> <p> The attenuation in a room depends on the location of the sound source and the receiver - and the room constant. </p> <h3> <a href="doppler-effect-d_1839.html" title="doppler effect frequency sound motion source listener"> Sound - Doppler Effect </a> </h3> <p> The doppler effect is the change in sound frequency due to the relative motion between a source and a listener. </p> <h3> <a href="sound-frequency-wavelength-d_56.html" title="sound noise wavelength octave frequency"> Sound - Frequency, Wavelength and Octave </a> </h3> <p> An introduction to the nature of sound with frequencies, wave-lengths and octaves. </p> <h3> <a href="age-shift-in-threshold-d_1474.html" title="men women age shift in threshold hz decibels"> Sound - Hearing Threshold vs. Age </a> </h3> <p> Shift in hearing threshold for men and women vs. age. </p> <h3> <a href="sound-level-d_719.html" title="outdoor sound ldn"> Sound - Ldn - Day and Night Level </a> </h3> <p> The EPA A-weighted sound level day and night equivalent definition - Ldn - for a 24 hour period. </p> <h3> <a href="equivalent-sound-level-d_721.html" title="equivalent sound level"> Sound - Leq - Equivalent Level </a> </h3> <p> The EPA Equivalent Sound Level - Leq - quantifies the noise environment to a single value of sound level for any desired duration. </p> <h3> <a href="sound-exposure-level-d_722.html" title="sound exposure level"> Sound - Ls - Exposure Level </a> </h3> <p> The EPA Sound Exposure Level - Ls - describes the noise from a variable source. </p> <h3> <a href="reverberation-time-d_724.html" title="sound reverberation time"> Sound - Reverberation Time </a> </h3> <p> The sound reverberation time indicates how long it takes until the sound pressure level in a room is decreased with 60 dB. </p> <h3> <a href="room-absorption-sound-d_69.html" title="sound acoustics absorption coefficients reverberation times"> Sound - Room Absorption Characteristics </a> </h3> <p> Mean absorption coefficients and reverberation times in typical rooms. </p> <h3> <a href="accoustic-sound-absorption-d_68.html" title="acoustic sound absorption coefficients"> Sound - Room Absorption Coefficients </a> </h3> <p> Room sound absorption and absorption coefficients for common materials like plaster walls, brickwork, plywood panels and more. </p> <h3> <a href="room-attenuation-d_1140.html" title="room attenuation direct sound field room size absorption characteristics"> Sound - Room Attenuation in Direct Sound Fields </a> </h3> <p> Room size, absorption characteristics - and attenuation in direct sound fields. </p> <h3> <a href="sound-attenuation-ducts-d_78.html" title="attentuation duct terminal"> Sound Attenuation - Duct split to Terminals </a> </h3> <p> Estimating sound attenuation where ducts splits to terminals. </p> <h3> <a href="sound-attenuation-ducts-branches-d_77.html" title="acoustics sound ducts hvac allowance main branch"> Sound Attenuation - Main Duct to Branch Ducts </a> </h3> <p> Sound attenuation from main ducts to branch ducts. </p> <h3> <a href="sound-attenuation-ducts-elbows-d_76.html" title="acoustics sound ducts elbows attenuation ventilation"> Sound Attenuation in Duct Elbows </a> </h3> <p> Noise attenuation in duct elbows by reflected sound. </p> <h3> <a href="sound-attenuation-end-reflection-d_73.html" title="sound acoustic noise reduction duct end reflection"> Sound Attenuation in Ducts due to End Reflection </a> </h3> <p> Low frequency noise transferred from main duct to end terminals is reflected back to main duct. </p> <h3> <a href="sound-intensity-d_712.html" title="sound intensity level"> Sound Intensity </a> </h3> <p> Acoustic power of sound per unit area. </p> <h3> <a href="sound-power-intensity-pressure-d_57.html" title="sound, noise, decibel, power, pressure, intensity"> Sound Intensity, Power and Pressure Levels </a> </h3> <p> Introduction to decibel, sound power, intensity and pressure. </p> <h3> <a href="sound-level-calculator-d_714.html" title="sound pressure calculator"> Sound Level - Online Calculator </a> </h3> <p> Calculate sound level, pressure and intensity. </p> <h3> <a href="sound-power-level-d_58.html" title="sound power level"> Sound Power </a> </h3> <p> Sound power from sources like fans, jet engines, cars, humans and more. </p> <h3> <a href="sound-pressure-d_711.html" title="sound pressure level force area "> Sound Pressure </a> </h3> <p> Sound Pressure is the force of sound on a surface perpendicular to the propagation of sound. </p> <h3> <a href="osha-maximum-sound-levels-d_1410.html" title="osha maximum sound levels work day dba"> Sound Pressure Level - OSHA A-Weighted per Day </a> </h3> <p> OSHA maximum A-weighted sound pressure levels allowed per day. </p> <h3> <a href="inverse-square-law-d_890.html" title="inverse square law sound noise decibel"> Sound Propagation - the Inverse Square Law </a> </h3> <p> Doubling of the distance from a noise source reduces the sound pressure level with 6 decibel. </p> <h3> <a href="sound-attenuation-ducts-walls-d_79.html" title="sound transmission duct wall"> Sound Transmission through Duct Walls </a> </h3> <p> Sound transmission from ducts to surrounding rooms. </p> <h3> <a href="sound-transmissions-flanking-paths-d_80.html" title="sound acoustics transmission flanke paths"> Sound Transmission through Flanking Paths </a> </h3> <p> Sound transmitted through duct walls, floors and ceilings. </p> <h3> <a href="sound-transmission-massive-walls-d_1409.html" title="sound transmission massive walls concrete"> Sound Transmission through Massive Walls or Floors </a> </h3> <p> Sound transmission and attenuation in building elements like massive concrete walls or floors. </p> <h3> <a href="speed-sound-d_82.html" title="sound speed materials air velocity"> Speed of Sound - Equations </a> </h3> <p> Calculate the speed of sound (the sonic velocity) in gases, fluids or solids. </p> <h3> <a href="speed-sound-d_519.html" title="speed sound air"> Speed of Sound - Online Calculator </a> </h3> <p> A free online speed of sound calculator. </p> <h3> <a href="sound-pressure-d_939.html" title="sound pressure level subjective loudness"> Subjective Effect of Change in Sound Pressure Level </a> </h3> <p> Change in sound pressure level and the subjective human perception. </p> <h3> <a href="sound-attenuation-ducts-d_74.html" title="sound acoustics reduction attenuation ducts"> Unlined Sheet-Metal Ducts - Sound Attenuation </a> </h3> <p> Noise attenuation in unlined sheet-metal ducts. </p> <h3> <a href="telephone-noise-d_1139.html" title="telephone noise noisy dbA sil"> Use of Telephones in Noisy Areas </a> </h3> <p> Satisfactory, difficult and impossible noise levels for telephone use in noisy areas. </p> <h3> <a href="accoustic-calculation-ventilation-d_70.html" title="acoustic sound noise ventilation reduction pressure decibel"> Ventilation Systems - Acoustic Calculation Procedure </a> </h3> <p> Acoustic noise calculation procedure HVAC systems. </p> <h3> <a href="noise-reduction-silencers-d_81.html" title="acoustics sound silencers noise reduction"> Ventilation Systems - Classification of Noise Reduction Silencers </a> </h3> <p> Noise in a ventilation system can be reduced by reactive, diffuser type, active and/or dissipative silencers. </p> <h3> <a href="sound-speed-water-d_598.html" title="water speed sound velocity temperature"> Water - Speed of Sound vs. Temperature </a> </h3> <p> Speed of sound in water at temperatures ranging 32 - 212掳F (0 - 100掳C) - Imperial and SI units. </p> </div> </div> <div id="adSlotStickyRight" class="noPrint"> <div>  <div id="adngin-right-0"></div> </div> </div> <div id="below"> <div> <h2> Search </h2> <script async src="https://cse.google.com/cse.js?cx=6a091aba9f3e1fba3"></script> <div class="gcse-searchbox-only"></div> <p> Search is the most efficient way to navigate the Engineering ToolBox. </p> <ul> <li> <a href="search-engineering-toolbox-d_2075.html"> Popular internal searches in the Engineering ToolBox </a> </li> </ul> </div> <div id="sketchup"> <h2> Engineering ToolBox - SketchUp Extension - Online 3D modeling! </h2> <p class="center"> <a href="https://sketchup.engineeringtoolbox.com" title="3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model"> <img src="https://www.engineeringtoolbox.com/docs/img/sketchup_700.gif" alt="3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model" height="95" width="700" loading="lazy" > </a> </p> <p> Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your <a href="https://www.sketchup.com"> Sketchup model </a> with the <a href="https://sketchup.engineeringtoolbox.com"> Engineering ToolBox - SketchUp Extension </a> - enabled for use with older versions of the amazing <a href="https://www.google.com/search?q=sketchup+make+old+download"> SketchUp Make </a> and the newer "up to date" <a href="https://www.google.com/search?q=sketchup+pro"> SketchUp Pro </a> . Add the <a href="https://extensions.sketchup.com/extension/99d3eb24-a56f-4c3e-b7cb-3550cd9d2aca/the-engineering-tool-box"> Engineering ToolBox extension </a> to your SketchUp Make/Pro from the <a href="https://extensions.sketchup.com/extension/99d3eb24-a56f-4c3e-b7cb-3550cd9d2aca/the-engineering-tool-box"> Extension Warehouse </a> !</p> </div> <div id="translate"> <h2> Translate this Page </h2> <p> Translate this page to <a href="https://translate.google.com/translate?u=www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html%26langpair=en%7Ces%26hl=en%26ie=UTF-8%26oe=UTF-8%26prev=%2Flanguage_tools"> Your Own Language </a> .</p> </div> <div id="aboutus"> About the Engineering ToolBox! </div> <div id="privacy"> <h2> Privacy Policy </h2> <p> We don't collect information from our users. More about </p> <ul> <li> <a href="privacy-policy-d_2228.html"> the Engineering ToolBox Privacy Policy </a> </li> </ul> <p>We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy <a href="https://www.snigel.com/privacy-policy/">here</a>.</p> <p> You can change your privacy settings by clicking the following button: <button onclick="adconsent('showGUI')">Manage Consent</button>. </p> </div> <div id="advertise"> <h2> Advertise in the ToolBox </h2> <p> If you want to promote your products or services in the Engineering ToolBox - please use <a href="https://adwords.google.com/"> Google Adwords. </a> You can target the Engineering ToolBox by using <a href="https://support.google.com/adwords/answer/2470108?hl=en"> AdWords Managed Placements. </a> </p> </div> <div id="citation"> <h2> Citation </h2> <p> This page can be cited as </p> <ul> <li> The Engineering ToolBox (2009). <i>Acoustics</i>. [online] Available at: https://www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html [Accessed Day Month Year]. </li> </ul> <p> Modify the access date according your visit. </p> </div> </div> </div> <div id="left"> <div id="apps"> <a title="3D Engineering ToolBox - 3D modelling technical applications!" href="//sketchup.engineeringtoolbox.com"> <img src="static/img/sketchup2.png" alt="3D Engineering ToolBox - draw and model technical applications!" loading="lazy" > </a> <a title="2D Engineering ToolBox - create and share online diagram drawing templates!" href="//www.engineeringtoolbox.com/2d-drawing-diagram-template-t_62.html"> <img src="static/img/googleDrawing.png" alt="2D Engineering ToolBox - create and share online diagram drawing templates!" loading="lazy" > </a> <a title="Engineering ToolBox Apps - mobile online and offline engineering applications!" href="//apps.engineeringtoolbox.com"> <img src="static/img/apps.png" alt="Engineering ToolBox Apps - mobile online and offline engineering applications!" loading="lazy" > </a> </div> <div id="menu"> <ul> <li id="t_27" class="menuItem"> <a href="acoustics-noise-decibels-t_27.html"> Acoustics </a> </li> <li id="t_8" class="menuItem"> <a href="air-psychrometrics-properties-t_8.html"> Air Psychrometrics </a> </li> <li id="t_19" class="menuItem"> <a href="si-units-engineering-t_19.html"> Basics </a> </li> <li id="t_9" class="menuItem"> <a href="combustion-boiler-fuels-t_9.html"> Combustion </a> </li> <li id="t_61" class="menuItem"> <a href="drawing-tools-t_61.html"> Drawing Tools </a> </li> <li id="t_60" class="menuItem"> <a href="dynamics-t_60.html"> Dynamics </a> </li> <li id="t_53" class="menuItem"> <a href="engineering-economics-t_53.html"> Economics </a> </li> <li id="t_33" class="menuItem"> <a href="electrical-systems-t_33.html"> Electrical </a> </li> <li id="t_13" class="menuItem"> <a href="environment-climate-meterology-t_13.html"> Environment </a> </li> <li id="t_21" class="menuItem"> <a href="fluid-mechanics-t_21.html"> Fluid Mechanics </a> </li> <li id="t_22" class="menuItem"> <a href="gas-air-systems-t_22.html"> Gases and Compressed Air </a> </li> <li id="t_23" class="menuItem"> <a href="hvac-systems-t_23.html"> HVAC Systems </a> </li> <li id="t_59" class="menuItem"> <a href="hydraulic-pneumatic-systems-t_59.html"> Hydraulics and Pneumatics </a> </li> <li id="t_4" class="menuItem"> <a href="insulation-heat-loss-t_4.html"> Insulation </a> </li> <li id="t_24" class="menuItem"> <a href="material-properties-t_24.html"> Material Properties </a> </li> <li id="t_54" class="menuItem"> <a href="mathematics-t_54.html"> Mathematics </a> </li> <li id="t_52" class="menuItem"> <a href="mechanics-t_52.html"> Mechanics </a> </li> <li id="t_25" class="menuItem"> <a href="engineering-topics-t_25.html"> Miscellaneous </a> </li> <li id="t_31" class="menuItem"> <a href="physiology-t_31.html"> Physiology </a> </li> <li id="t_6" class="menuItem"> <a href="piping-tubing-systems-t_6.html"> Piping Systems </a> </li> <li id="t_32" class="menuItem"> <a href="process-control-systems-t_32.html"> Process Control Systems </a> </li> <li id="t_34" class="menuItem"> <a href="pumps-t_34.html"> Pumps </a> </li> <li id="t_75" class="menuItem"> <a href="sanitary-drainage-systems-t_75.html"> Sanitary Drainage Systems </a> </li> <li id="t_48" class="menuItem"> <a href="standards-organizations-t_48.html"> Standard Organizations </a> </li> <li id="t_63" class="menuItem"> <a href="statics-t_63.html"> Statics </a> </li> <li id="t_28" class="menuItem"> <a href="steam-condensate-properties-t_28.html"> Steam and Condensate </a> </li> <li id="t_36" class="menuItem"> <a href="thermodynamics-t_36.html"> Thermodynamics </a> </li> <li id="t_29" class="menuItem"> <a href="hot-water-systems-t_29.html"> Water Systems </a> </li> </ul> </div> <div id="convert"> <h3> <a href="unit-converter-d_185.html"> Unit Converter </a> </h3> <br > <blockquote> <label for="temperature_value2"> <a href="temperature-d_291.html"> Temperature </a> </label> <input type="number" id="temperature_value2" value="0.0" > <input type="radio" name="temperature_unit2" value="degC" id="temperature_unit2_degC" checked="checked" > <label for="temperature_unit2_degC"> <i><sup>o</sup>C</i> </label> <br > <input type="radio" name="temperature_unit2" id="temperature_unit2_degK" value="degK" > <label for="temperature_unit2_degK"> <i>K</i> </label> <br > <input type="radio" name="temperature_unit2" id="temperature_unit2_degF" value="degF" > <label for="temperature_unit2_degF"> <i><sup>o</sup>F</i> </label> <br > <input type="button" id="temperature_calculate2" value="Convert!" > <div id="resultMenuTemperature"> </div> </blockquote> <br > <blockquote> <label for="length_value2"> <a href="length-units-converter-d_1033.html"> Length </a> </label> <input type="number" id="length_value2" value="1.0" > <input type="radio" name="length_unit2" id="length_unit2_meters" value="meters" checked="checked" > <label for="length_unit2_meters"> <i>m</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_kilometers" value="kilometers" > <label for="length_unit2_kilometers"> <i>km</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_inches" value="inches" > <label for="length_unit2_inches"> <i>in</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_feet" value="feet" > <label for="length_unit2_feet"> <i>ft</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_yards" value="yards" > <label for="length_unit2_yards"> <i>yards</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_miles" value="miles" > <label for="length_unit2_miles"> <i>miles</i> </label> <br > <input type="radio" name="length_unit2" id="length_unit2_nautical_miles" value="nautical_miles" > <label for="length_unit2_nautical_miles"> <i>naut miles</i> </label> <br > <input type="button" id="length_calculate2" value="Convert!" > <div id="resultMenuLength"> </div> </blockquote> <br > <blockquote> <label for="area_value2"> <a href="area-units-converter-d_2007.html"> Area </a> </label> <input type="number" id="area_value2" value="1.0" > <input type="radio" name="area_unit2" id="area_unit2_square_meters" value="sq.meters" checked="checked" > <label for="area_unit2_square_meters"> <i>m<sup>2</sup></i> </label> <br > <input type="radio" name="area_unit2" id="area_unit2_square_kilometers" value="sq.kilometers" > <label for="area_unit2_square_kilometers"> <i>km<sup>2</sup></i> </label> <br > <input type="radio" name="area_unit2" id="area_unit2_square_inches" value="sq.inches" > <label for="area_unit2_square_inches"> <i>in<sup>2</sup></i> </label> <br > <input type="radio" name="area_unit2" id="area_unit2_square_feet" value="sq.feet" > <label for="area_unit2_square_feet"> <i>ft<sup>2</sup></i> </label> <br > <input type="radio" name="area_unit2" id="area_unit2_square_miles" value="sq.miles" > <label for="area_unit2_square_miles"> <i>miles<sup>2</sup></i> </label> <br > <input type="radio" name="area_unit2" id="area_unit2_acres" value="acres" > <label for="area_unit2_acres"> <i>acres</i> </label> <br > <input type="button" id="area_calculate2" value="Convert!" > <div id="resultMenuArea"> </div> </blockquote> <br > <blockquote> <label for="volume_value2"> <a href="volume-units-converter-d_1034.html"> Volume </a> </label> <input type="number" id="volume_value2" value="1.0" > <input type="radio" name="volume_unit2" id="volume_unit2_cubic_meters" value="cubic_meters" checked="checked" > <label for="volume_unit2_cubic_meters"> <i>m<sup>3</sup></i> </label> <br > <input type="radio" name="volume_unit2" id="volume_unit2_liters" value="liters" > <label for="volume_unit2_liters"> <i>liters</i> </label> <br > <input type="radio" name="volume_unit2" id="volume_unit2_cubic_inches" value="cubic_inches" > <label for="volume_unit2_cubic_inches"> <i>in<sup>3</sup></i> </label> <br > <input type="radio" name="volume_unit2" id="volume_unit2_cubic_feet" value="cubic_feet" > <label for="volume_unit2_cubic_feet"> <i>ft<sup>3</sup></i> </label> <br > <input type="radio" name="volume_unit2" id="volume_unit2_us_liquid_gallons" value="us_liquid_gallons" > <label for="volume_unit2_us_liquid_gallons"> <i>us gal</i> </label> <br > <input type="button" id="volume_calculate2" value="Convert!" > <div id="resultMenuVolume"> </div> </blockquote> <br > <blockquote> <label for="weight_value2"> <a href="mass-weight-d_589.html"> Weight </a> </label> <input type="number" id="weight_value2" value="1.0" > <input type="radio" name="weight_unit2" id="weight_unit2_kgf" value="kgf" checked="checked" > <label for="weight_unit2_kgf"> <i>kg<sub>f</sub></i> </label> <br > <input type="radio" name="weight_unit2" id="weight_unit2_N" value="N" > <label for="weight_unit2_N"> <i>N</i> </label> <br > <input type="radio" name="weight_unit2" id="weight_unit2_lbf" value="lbf" > <label for="weight_unit2_lbf"> <i>lbf</i> </label> <br > <input type="button" id="weight_calculate2" value="Convert!" > <div id="resultMenuWeight"> </div> </blockquote> <br > <blockquote> <label for="velocity_value2"> <a href="velocity-units-converter-d_1035.html"> Velocity </a> </label> <input type="number" id="velocity_value2" value="1.0" > <input type="radio" name="velocity_unit2" id="velocity_unit2_m_per_s" value="m_per_s" checked="checked" > <label for="velocity_unit2_m_per_s"> <i>m/s</i> </label> <br > <input type="radio" name="velocity_unit2" id="velocity_unit2_km_per_h" value="km_per_h" > <label for="velocity_unit2_km_per_h"> <i>km/h</i> </label> <br > <input type="radio" name="velocity_unit2" id="velocity_unit2_ft_per_min" value="ft_per_min" > <label for="velocity_unit2_ft_per_min"> <i>ft/min</i> </label> <br > <input type="radio" name="velocity_unit2" id="velocity_unit2_ft_per_s" value="ft_per_s" > <label for="velocity_unit2_ft_per_s"> <i>ft/s</i> </label> <br > <input type="radio" name="velocity_unit2" id="velocity_unit2_mph" value="mph" > <label for="velocity_unit2_mph"> <i>mph</i> </label> <br > <input type="radio" name="velocity_unit2" id="velocity_unit2_knots" value="knots" > <label for="velocity_unit2_knots"> <i>knots</i> </label> <br > <input type="button" id="velocity_calculate2" value="Convert!" > <div id="resultMenuVelocity"> </div> </blockquote> <br > <blockquote> <label for="pressure_value2"> <a href="pressure-units-converter-d_569.html"> Pressure </a> </label> <input type="number" id="pressure_value2" value="1.0" > <input type="radio" name="pressure_unit2" id="pressure_unit2_Pa" value="Pa" checked="checked" > <label for="pressure_unit2_Pa"> <i>Pa</i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_bar" value="bar" > <label for="pressure_unit2_bar"> <i>bar</i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_atmosphere" value="atmosphere" > <label for="pressure_unit2_atmosphere"> <i>atmosphere</i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_mmH2O" value="mmH2O" > <label for="pressure_unit2_mmH2O"> <i>mm H<sub>2</sub>O</i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_kg_per_cm2" value="kg_per_cm2" > <label for="pressure_unit2_kg_per_cm2"> <i>kg/cm<sup>2</sup></i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_psi" value="psi" > <label for="pressure_unit2_psi"> <i>psi</i> </label> <br > <input type="radio" name="pressure_unit2" id="pressure_unit2_inH2O" value="inH2O" > <label for="pressure_unit2_inH2O"> <i>inches H<sub>2</sub>O</i> </label> <br > <input type="button" id="pressure_calculate2" value="Convert!" > <div id="resultMenuPressure"> </div> </blockquote> <br > <blockquote> <label for="flow_value2"> <a href="flow-units-converter-d_405.html"> Flow </a> </label> <input type="number" id="flow_value2" value="1.0" > <input type="radio" name="flow_unit2" id="flow_unit2_cubic_meters_per_second" value="cubic_meters_per_second" checked="checked" > <label for="flow_unit2_cubic_meters_per_second"> <i>m<sup>3</sup>/s</i> </label> <br > <input type="radio" name="flow_unit2" id="flow_unit2_cubic_meters_per_hour" value="cubic_meters_per_hour" > <label for="flow_unit2_cubic_meters_per_hour"> <i>m<sup>3</sup>/h</i> </label> <br > <input type="radio" name="flow_unit2" id="flow_unit2_us_gallons_per_minute" value="us_gallons_per_minute" > <label for="flow_unit2_us_gallons_per_minute"> <i>US gpm</i> </label> <br > <input type="radio" name="flow_unit2" id="flow_unit2_cubic_feet_per_minute" value="cubic_feet_per_minute" > <label for="flow_unit2_cubic_feet_per_minute"> <i>cfm</i> </label> <br > <input type="button" id="flow_calculate2" value="Convert!" > <div id="resultMenuFlow"> </div> </blockquote> </div> <p id="tstamp"> 11.25.10 </p> <div id="adSlotStickyLeft" class="noPrint"> <div>  <div id="adngin-left1-0"></div> </div> </div> <a href="/amp/acoustics-noise-decibels-t_27.html" title="amp page"> . </a> </div> <div id="right"> <div id="share"> <p> <a title="Print page!" href="#" id="printer_friendly"> <img src="static/img/printer.png" width="60" height="20" alt="printer friendly" loading="lazy" > </a> </p> <p> <a title="Shortcut to Home Screen" href="shortcut-webpage-homescreen-desktop-d_2230.html"> Make Shortcut to Home Screen? </a> </p> </div> </div> <script> var reload = false; var host = window.location.hostname; if (host.indexOf("www.engineeringtoolbox.com") == -1) reload = true; if (host.indexOf("localhost") != -1) reload = false; if (host == "") reload = false; reload = false; if (reload) { var canUrl = "https://www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html"; setTimeout(function(){location.href = canUrl;} , 3000); } </script>  <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-WH8MKZX" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <div id="adAnchor" class="noPrint">  <div id="adngin-adhesive-0"></div> </div> </body> </html>