Sound Level Meter
When purchasing a sound level meter, look for a brand with a good reputation for quality and reliability, and consider additional features.
When purchasing a sound level meter, look for a brand with a good reputation for quality and reliability, and consider additional features.
Must know
A sound level meter is an electronic device that measures the sound pressure level (SPL) of a sound wave. It is handheld and consists of a microphone that captures sound, an amplifier that increases the signal strength, and a display unit that shows the SPL in decibels (dB). To use a sound pressure level meter, you place the microphone at the desired location (e.g. at 10-40 cm distance to a human ear) and read the SPL on the display unit.
It is crucial to calibrate the device regularly to ensure accurate measurements. Calibration involves adjusting the device to match a known standard or reference value, which can be done using a calibration sound source or a sound calibrator.
A sound level meter can be designed to measure different frequency ranges and can have various features, such as data logging, A/C weighting, and time weighted fast or slow response. Data logging allows you to record and analyze SPL sound pressure level over time, while A/C weighting adjusts the readings to account for human hearing sensitivity. Fast or slow response times refer to the speed at which the device responds to changes in sound level.
Sound level meters are classified into different classes, such as Class 1 or Class 2, depending on their level of accuracy and performance. Class 1 meters are more accurate and suitable for more precise measurements, while Class 2 meters are less accurate but still provide reliable readings.
When selecting a sound level meter, you should consider the application, the frequency range required for the specific application, the accuracy of the sound level meter, and any additional features that may be necessary for your specific application. You should also consider the brand, reputation, and specific features required for your application, as well as the overall cost-benefit ratio of the device.
Some best practices for using a sound level meter include regularly calibrating the device according to the manufacturer’s instructions to ensure accurate and reliable measurements. It’s also essential to be aware of the environmental conditions and ambient noise levels, and to calibrate the sound level meter in a quiet and controlled environment whenever possible to reduce interference from background noise.
Sound level meters are commonly used in various industries and settings, such as occupational safety, environmental monitoring, and sound engineering. They can be used to measure noise levels in factories, construction sites, and music venues, as well as to monitor traffic noise and aircraft noise in residential areas.
A sound level meter is a useful tool for anyone who needs to measure or monitor sound levels. It can help you comply with noise measurements regulations, protect your hearing health, monitor noise pollution, or optimize sound quality. Specifically, it can help you:
There are different types of sound level meters available on the market, and they are classified based on their performance and accuracy. The two most common types are Class 1 and Class 2, which are defined by international standards.
Organizations like ISO, IEC, and ANSI all use the term “sound level meter” as their standard name. Professionals in the field tend to use this term. However, non-professionals may use the terms “sound” and “noise” interchangeably and may refer to outdoor noise monitors as “noise meters.” It is important to note that these terms may not accurately describe the device’s capabilities or accuracy.
Several variables can impact the accuracy of a sound level meter, including the quality of the device, calibration, and adherence to international standards. Typically, higher-quality and more expensive sound level meters are more accurate than cheaper models.
According to IEC 61672 standards, the accuracy of a sound level meter is dependent on frequency, with the most significant accuracy provided at 1 kHz, which is the frequency used to check the SLM calibration.
At 1 kHz, the accuracy of Class 1 meters is +/- 0.7 dB, while for Class 2 meters, it’s +/- 1 dB. As the frequency moves further away from 1 kHz, the accuracy difference between Class 1 and Class 2 meters increases. For instance, at 4 kHz, the Class 1 accuracy is +/- 1 dB and Class 2 is +/- 3 dB.
It’s worth noting that certain low-cost decibel meters marketed for sound exposure measurements may not always be reliable or accurate. These meters may use low-quality components like microphones or amplifiers or they may be calibrated improperly. Additionally, they may not meet accuracy standards established by organizations such as the International Electrotechnical Commission (IEC) or the American National Standards Institute (ANSI).
The frequency range of a sound level meter refers to the range of frequencies that the device can measure. Professional sound level meters follow standards set by organizations such as the International Electrotechnical Commission (IEC) and provide a specific frequency range. It is important to note that these frequencies are the middle frequencies of 1/3 octave bands.
In addition to the standard frequency range, there are also specialized sound level meters that can measure:
When selecting a sound level meter, it is important to consider, if the application requires the measurement of ultrasounds or infrasound waves, it is crucial to choose a microphone specifically designed for these purposes.
IEC and ANSI meters often quote a frequency range up to 20 kHz because it covers the entire audible range for humans, from the lowest audible frequency of 20 Hz to the highest audible frequency of 20 kHz.
It’s worth noting that on the upper end of the frequency range, the error margin for IEC and ANSI meters can be quite large. Specifically, for Class 1 meters, the error margin at 20 kHz ranges from +4 dB to negative infinity, indicating that accuracy is not guaranteed at this frequency in practice. As a result, professionals in the field recognize that 16 kHz is the upper limit of the audible range that can be accurately measured using a Class 1 sound level meter.
Regular calibration is essential to maintaining the accuracy and reliability of professional devices. Calibration involves adjusting the device to match a known reference standard, such as a sound calibrator. Sound level meters can drift over time due to various factors, including environmental conditions and component wear and tear. Even slight deviations from the reference standard can result in significant measurement errors and affect compliance with standards or regulations.
The frequency of calibration required for a sound level meter depends on its application. As a general rule, a professional meter should be calibrated by an accredited laboratory every 1-2 years. In addition to this, users should perform an acoustic calibration using a sound calibrator before and after a series of daily measurements.
The frequency of calibration depends on the type and quality of the sound level meter as well as the specific regulations or standards that apply to the application. Regulations may require annual calibration, while some industries may require more frequent calibration.
A certified technician, calibration software, and a reference standard can both perform calibration. Following the manufacturer’s instructions and calibration procedures for the specific sound level meter is crucial to ensuring accurate and reliable measurements.
RMS, AC signal, and DC signal are terms commonly used in the context of sound level meters and audio signals. Understanding these concepts can be helpful when using a sound level meter or working with audio signals:
Using your phone as a dBA meter can be a convenient and cost-effective option for basic noise survey tasks. However, it’s crucial to keep in mind that a number of factors may affect the measurement’s accuracy.
Firstly, it’s important to note that the accuracy of your measurement can be affected by the quality of the microphone on your phone. Some phones have better microphones than others, and over time, the microphone quality can deteriorate. Furthermore, the placement of the microphone on your phone may interfere with or block the measurement due to your hand or other objects.
Secondly, the sound meter app that you use can also affect the accuracy of the measurement. Not all sound meter applications are created equal, and some may use different algorithms or calibration procedures than others. Choosing a reputable and well-reviewed sound level meter application and calibrating it properly according to instructions is crucial.
It’s worth noting that phones are not calibrated according to IEC standards, which means that their readings cannot be traced, and their frequency response is not accounted for. As a result, readings obtained from a noise level meter on a phone are considered a survey rather than a measurement due to the lack of traceability.
Professional sound level meters use apps only as an extension. For example, the SLM app can be used to calculate sound insulation or STIPA from the sound level meter’s data.
If you are considering purchasing a sound level meter, several factors need to be taken into account:
Sound level meters can have several standard and optional features in addition to measuring the sound pressure level (SPL). Some of the standard features include:
In addition to standard functions, a professional SLM can be upgraded with several application-specific options, such as:
Consider whether the above features are necessary for your specific application when selecting a sound level meter.
When choosing a sound level meter, it is essential to consider the brand, reputation, and specific features required for your application.
Several professional brands produce high-quality sound and vibration instruments for various applications, including sound level meters. Some of the popular brands include:
The price of sound level meters can vary widely depending on their type, accuracy, and features. Here is a rough breakdown of the price range for different types of sound level meters:
When choosing a sound meter, it is essential to consider your specific needs and accuracy requirements, as well as the overall cost-benefit ratio of the device. Keep in mind that calibration services and accessories, such as windshields or tripods, may add to the overall cost.
Sound level meter apps and software are necessary for calculations of final noise results and reporting. Here are the options for Svantek apps and software:
These apps and software can be helpful for various applications, such as work environments, outdoor monitoring, and building acoustics.
The American National Standards Institute (ANSI) has established Standard S12.60 for Classroom Acoustics. This standard sets maximum levels for reverberation times (RT60) and background noise. These maximum levels are applicable in classrooms.
To comply with regulations, a classroom noise meter, such as the SV 973 with RT60 and STIPA options installed, can be used. A professional Class 2 SLM is typically sufficient for classroom use, as it is accurate enough and less expensive than a Class 1 meter.
When using a noise level meters, several best practices are crucial to keep in mind:
Several misconceptions about sound level meters are important to address. First, some people may assume that any device to measure decibels is accurate and reliable, regardless of the brand or model. In reality, the accuracy and reliability of an acoustic meter can vary widely depending on several factors, such as the type, calibration, and environmental conditions.
Second, some people may assume that using a noise measurement tool is straightforward and easy without realizing the potential for errors or misunderstandings in measurement and interpretation. Third, some people may assume that all dB meters are equally suitable for any application, without considering the specific requirements and standards for their industry or application. It is important to be aware of these misconceptions and to take steps to ensure accurate and reliable measurements with a sound level meter.
An authorized SVANTEK consultant will help You with the details such as the required accessories for your noise monitoring task.
