What is sound level meter

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what is sound level meter

Read more. Known as telehealth audiology, it's growing in popularity for rural or housebound patients. Even though your child's hearing is normal, they may have problems understanding what their ears are hearing.

what is sound level meter

To help people who are deaf or hearing impaired, common signs and symbols are used to indicate if a location has assistive technology, such as closed captioning or loop induction systems.

Will the roar of the crowd be enough to warrant wearing ear protection? Is the music too loud for your guests and the neighbors? This highly-rated, free app turns your smartphone into a pre-calibrated, accurate and easily portable sound level meter.

It has a standard measurement range from 30 to dB. It boasts many features for measuring the intensity of sound around you built into a nicely-designed, intuitive user interface. This professional-grade sound level meter is measured after a traditional sound press level SPL meter, including ballistics, ranges, filters and decay rates. The app comes pre-calibrated for most mobile devices but can be adjusted to match professional calibrated meters.

The universal app can be shared on all devices. A simple color-coded display indicates safe green and dangerous red hearing levels. This easy-to-use app is built specifically for measuring noise levels in environments where there are groups of children. Teachers and other childcare workers can adjust the sensitivity of the app to cater to louder activities and sudden noises with the sensitivity and dampening sliders.

It can raise employees' awareness about the noise levels in their workplace, help them make informed decisions about their hearing health and determine when hearing protection is necessary. Researchers can also use the app to collect data about noise exposure. Designed by a signal processing expert, the advanced features on this app for iOS devices include a frequency analyzer, frequency meter, test signal generator and dosimeter. A simple interface displays the level of exposure using color—orange or red indicates dangerous levels where 50 best riddles protection is required.

Because the microphones in Android devices are used to record human voices, the maximum levels on this app are limited and sounds above dB are not recognized. Like most sound meter apps, this one uses your smartphone microphone to measure the sound in your environment. The decibel level is displayed on an easy-to-read dial.

what is sound level meter

These apps can be very helpful in specific situations, but they are not a replacement for good hearing healthcare or properly fit hearing aids.A sound level meter is used for acoustic measurements. The word "acoustic" means "sound that travels through air". This is opposed to the word "audio", a term that is also often used in the field of sound measurement.

That having being said, let's get back to acoustic measurements. A sound level meter needs a microphone to measure the changes in air pressure produced by the sound source. The better quality the microphone, the more accurate the measurements will be.

Such measurement microphones are categorized as Class 1 or Class 2. For many applications a Class 2 microphone, which is slightly less accurate and less pricey than a Class 1 microphone, is more than sufficient.

Class 1 microphones are usually only required when the law prescribes. Whichever microphone you use, it is important for accuracy that the microphone is correctly calibrated.


The single value measured by a sound level meter is referred to as the "broadband value" as it uses all values across the audio frequency bands 20 Hz to 20 kHz to calculate the level. It is typically measured in decibels dBwhich is a logarithmic unit.

This means, for example, that doubling the sound level would correspond to a 10 dB higher measurement value. The spectrum of frequencies provided by an RTA measurement suits tasks such as optimization of sound systems and rooms.

To conceptualize this, one can think of a piano. What is a Sound Level Meter A sound level meter is used for acoustic measurements.

Broadband Level.The app was developed to help workers make informed decisions about their noise environment and promote better hearing health and prevention efforts.

Download the free app today external icon. Download the user manual pdf icon. The NIOSH Sound Level Meter app has many important features, it provides a readout of the sound level using the built-in microphone or external microphone if used and reports the instantaneous sound level in A, C, or Z-weighted decibels.

The app also contains some basic information on noise and hearing loss prevention. In addition, the app allows the user to save and share measurement data using the smartphone other communication and media features.

If location services are enabled, the app can utilize the GPS feature to provide an exact geospatial location of the noise measurement. Note: Professional sound level meters must comply with a host of acoustical and electrical tests to meet national and international standards.

NIOSH estimates that there are 22 million workers who are exposed to hazardous noise levels every year. During our studies, we realized that most of the apps on the market are oriented at the casual user and lack the accuracy and functionality necessary to conduct occupational and general purpose noise measurements.

NIOSH hearing loss researchers collaborated with an app developer, EA LAB, to create an iOS based sound level meter app that measures and characterizes occupational noise exposure similar to professional instruments. In addition, the app can serve as a research tool for scientists and occupational safety and health professionals to collect noise exposure data and promote better hearing health and prevention efforts.

The REL for noise is 85 decibels, using the A-weighting frequency response an 8-hour average, usually referred to as time-weighted average TWA. Exposures at or above this level are considered hazardous. OSHA sets legally-enforceable permissible exposure limit PEL that require employers to take actions to reduce worker exposures.

Occupational standards specify a maximum allowable daily noise dose, expressed in percentages. The noise dose is based on both the sound exposure level and how long it lasts duration. This dose limit uses a 3-dB time-intensity tradeoff commonly referred to as the exchange rate or equal-energy rule: for every 3-dB increase in averaged noise exposure, the allowable exposure time is reduced by half.

For example, if the exposure increases to 88 dB Aworkers should only be exposed for four hours. Alternatively, for every 3-dB decrease in averaged noise exposure, the allowable exposure time is doubled, as shown in the table below. It is important to differentiate between noise level and time-weighted average noise exposure.

While noise levels describe the intensity of sounds at a given point in time, the NIOSH exposure limits are set as time-weighted average exposures over periods of time. If noise level measurements consistently exceed 85 dB Awe recommend that you follow up with a professional such as an industrial hygienist or an occupational safety and health specialist to conduct a professional noise survey at your workplace.

Remember, protecting your hearing is a good health practice no matter where your ears are! As a result, testing and verification of the accuracy and functionality of an Android-based app in our laboratory is not currently possible. Please send us feedback here. Evaluation of smartphone sound measurement applications external icon — Journal of Acoustical Society of America.Built-in smart integrating algorithms and wide measuring range dB competent in most rigorous industrial use.

Measures and displays Leq value. Low power combustion and USB port charging allow long hour usage. This standard specifies two levels of performance, Class 1 and Class 2, with Class 1 being effectively more accurate. Within the standard are a set of performance criteria that an instrument must meet and each of these has a tolerance associated with it. The tolerances for Class 1 are tighter than for Class 2. A simple sound level meter that meets the standard may only provide Sound Pressure measurements whereas a much more sophisticated instrument may provide for the measurement of Sound Pressure, Leq and Peak Sound Pressure.

Whether you need a Class 1 or a Class 2 sound level meter will depend largely upon the application that you will be using the instrument for. If you are working to an environmental noise standard then this may specify that the instrument should be Class 1. This is particularly relevant for environmental noise surveys where low noise levels are being measured.

Finally, you may choose Type 1 for important legal applications as the evidence from the more accurate meter may be more convincing, even when the regulations do not demand it. Class 1 sound level meter is preferred for the design of cost-effective noise controls. Class 1 Integrated. High Precision.

Smart Integration. Wide Measurement. Get A Quote. Road Construction. Police Force. Data Sheet. IEC Class 1 3.

Class1 Calibrator data-sheet The sound level on a basic level - how loud something is can be perceived differently by different people so we need to have a means to get an objective measurement of sound level expressed in numerical terms. Sound pressure p is the average variation in atmospheric pressure caused by the sound. Sound pressure level SPL is the pressure level of a sound, measured in decibels dB.

Or, in other words is the ratio of the absolute sound pressure against a reference level of sound in the air.

The unit measure of SPL is decibels dB. Sound enters the meter through a microphone, and then the meter evaluates the sound values by converting them into electrical information and the measurement values in decibels are displayed. An SPL Meter is generally handheld, mobile and lightweight, and is manufactured in line with international standards such as IEC The meters will quickly take measurements of noise level and allow the user to identify sources or situations where noise might be an issue either for occupational noise at work reasons, for environmental pollution or for noisy neighbour disputes.

There are different Classes Types of meter - Class 1 Type 1 is more precise with the measurements than a Class 2 Type 2 because of the microphones used - but both will meet international standards for noise measurement and be accurate. A SPL meter typically displays a range of sound pressure levels from 20 dB to dB, although it is possible to measure lower and higher than this range.

Many can also be set to measure over long periods of time or at set intervals - this is particularly useful when measuring environmental noise or traffic noise for example. Using a mobile SPL meter enables the user to take the meter to where the noise is present, store the measurements in an internal memory and then download the measurements later for analysis, reporting and to identify appropriate control measures to be put in place to reduce noise. Please also refer to our Acoustic Glossary for explanation of noise measurement terms.

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How is it measured? What are decibels, the decibel Scale and noise measurement units? You are using a really old browser! You should upgrade to a different browser to get the full experience of our site.What is an Integrating Sound Level Meter? This is a common question we get asked when it comes to choosing noise measurement equipment. Definition : An integrating sound level meter is an instrument that measures sound energy over a period of time. Explanation : Picture a varying noise level drawn as a continuous line on a graph.

This varying line represents the continuously changing sound pressure which is measured by the microphone of the sound level meter and is measured in Pascals. When this is converted into a dB value which makes it easier to shown on the display of a sound level meter it is known as the Sound Pressure Level. This is where the term SPL comes from. The area underneath the line on the graph represents the sound energy accumulated over the measurement period.

By using a mathematical function known as integration, we can calculate this area and therefore calculate the sound energy.


This is what an integrating sound level meter does and this is known as the Sound Exposure which is measured in Pa 2 hr. If this is A-weighted, it will be show as L AE. To get an Leq value, or Equivalent Continuous Sound Level, we need to divide the sound exposure by the duration of the measurement.

what is sound level meter

This averages the sound exposure over the measurement time and gives us the Leq. In most modern sound level meters, this process is done behind the scenes, with the Leq being displayed as the primary value. An instrument such as the Cirrus Optimus Red range will accumulate the sound exposure over the measurement period, displaying a cumulative Leq as the measurement continues as well as showing the sound exposure level as an LE or L AE when it has been A-weighted.

Some instruments, such as the Cirrus Optimus Red and Optimus Green will also show the Sound Exposure value in Pa 2 hr as there are a few applications where this is still used.

By knowing the Leq value and the duration of the measurement, it is possible to calculate the Sound Exposure and Sound Exposure Levels if they are required. A sound level meter that measures and displayed Leq is often referred to as an integrating sound level meter but the technically correct description for a this type of instrument is an integrating-averaging sound level meter.

This is because the sound energy that has been measured has been averaged over a known time period. The previous standards for sound level meters were split into two separate parts. The first, IECcovered sound level meters without any integration. The second standard, IECcovered both integrating and integrating-averaging instruments. The current standard for sound level meters, IECcovers instruments that can be anything from simple sound level meters that just measure the Sound Pressure Level through to Integrating-Averaging Sound Level Meters that will be capable of time averaging the sound exposure and giving an Leq value.

Almost every occupational noise standard or regulation specify noise exposure limits as integrated noise values and to measure to these standards requires the use of an Integrating Sound Level Meter of some form. All of these are integrated noise values where the sound exposure has been time averaged over a measurement period.

There are differences between these different standards but the underlying principle is the same. According to the Control of Noise at Work Regulations, a sound level that will be used make measurement shoulda minimum, be capable of measuring:.

As the instrument needs to measure, at a minimum, Leq, it must therefore be an integrating-averaging sound level meter. Expand your Noise Knowledge!Sound-level meterdevice for measuring the intensity of noise, music, and other sounds. A typical meter consists of a microphone for picking up the sound and converting it into an electrical signal, followed by electronic circuitry for operating on this signal so that the desired characteristics can be measured. The indicating device is usually a meter calibrated to read the sound level in decibels dB; a logarithmic unit used to measure the sound intensity.

Threshold of hearing is about zero decibels for the average young listener, and threshold of pain extremely loud sounds is around decibels, representing a power 1, or 10 12 times greater than zero decibels. The electronic circuitry can be adjusted to read the level of most frequencies in the sound being measured or the intensity of selected bands of frequencies. The constant selected depends on the purpose for which the instrument was designed or for which it is being used.

A typical sound-level meter can be switched between a scale that reads sound intensities uniformly for most frequencies—called unweighted—and a scale that introduces a frequency-dependent weighting factor, thus yielding a response more nearly like that of the human ear.

A-frequency-weighting is the most commonly used standard, but B- C- D- and Z-frequency-weightings also exist. The A-frequency-weighting scale is useful in describing how complex noises affect people. Thus, the scale is recognized internationally for measurements relating to prevention of deafness from excessive noise in work environments. In the early s, as concern about noise pollution increased, accurate, versatile, portable noise-measuring instruments were developed.

Sound level is not a measure of loudness, as loudness is a subjective factor and depends on the characteristics of the ear of the listener. In an attempt to overcome this problem, scales have been developed to correlate loudness with objective measurements of sound. The Fletcher—Munson curvefor example, shows the relationship between loudness in decibels and subjectively judged loudness. Other variables have also been studied. Sound-level meter.

Info Print Cite. Submit Feedback. Thank you for your feedback. Sound-level meter instrument. See Article History. Get exclusive access to content from our First Edition with your subscription. Subscribe today. Learn More in these related Britannica articles:. Microphonedevice for converting acoustic power into electric power that has essentially similar wave characteristics.

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