What Device Is Used to Measure Noise?

The instrument most commonly used to measure noise is a sound level meter, also known as a noise meter or decibel meter. It measures sound pressure level and reports the result in decibels (dB). Sound level meters are used in environmental monitoring, industrial facilities, transportation, building acoustics and occupational noise assessments.

Other devices, including fixed noise sensors, personal noise dosimeters and acoustic analyzers, serve different measurement purposes. The appropriate instrument depends on whether the application requires a spot measurement, continuous monitoring, personal noise exposure assessment or detailed frequency analysis.

Which Instrument Is Used to Measure Noise?

A sound level meter is the standard general-purpose instrument for measuring sound pressure level at a specified location. It uses a microphone and electronic measurement circuitry to convert variations in air pressure into a sound-level reading.

For continuous monitoring, a fixed noise sensor or environmental noise monitoring system can provide repeated measurements to a data logger. For individual worker exposure, a personal noise dosimeter may be more appropriate.

How Does a Sound Level Meter Work?

Sound consists of pressure variations traveling through a medium such as air. A sound level meter detects these variations using a microphone, converts them into electrical signals and processes the signals to calculate sound pressure level.

A typical measurement instrument includes a microphone, signal-conditioning electronics, frequency-weighting and measurement-processing functions, and a display or output interface.

The available weighting modes, integration functions, frequency analysis and reporting outputs depend on the instrument model. Not every noise meter includes the complete set of functions used in professional acoustic assessment.

What Does dB Mean in Noise Measurement?

The decibel (dB) is a logarithmic unit. In airborne sound measurement, sound pressure level expresses the measured pressure relative to a standard reference sound pressure of 20 micropascals (20 μPa).

Because the scale is logarithmic, a change of 10 dB does not represent a simple increase of 10 units in physical sound pressure. A 20 dB increase corresponds to a tenfold increase in sound pressure amplitude, assuming the same reference and measurement conditions.

The meaning of a reported sound level also depends on its frequency weighting, time weighting or averaging method. For example, a value expressed in dB(A) indicates A-weighted sound level.

dB, dBA, LAeq and Lmax: What Is the Difference?

A single noise reading may not provide sufficient information for every environmental or occupational assessment. Different sound-level indicators describe different aspects of a noise event.

For instance, LAeq,T represents an energy-equivalent average over a specified duration. It is not simply the arithmetic average of several values expressed in decibels.

A fixed sensor that provides a sound-level reading should not automatically be assumed to calculate LAeq, maximum sound levels, peak levels or noise exposure dose. These functions must be verified against the selected instrument's specifications.

Sound Level Meter vs Noise Sensor vs Dosimeter

The three instruments are related, but they are not interchangeable in every measurement project.

Sound Level Meter

A portable sound level meter is commonly selected for checking sound levels at individual locations, investigating machinery noise and conducting appropriate environmental or acoustic measurements. Higher-function instruments may also support time averaging, frequency analysis and data logging.

Fixed Noise Monitoring Sensor

A fixed noise sensor is suitable for continuous monitoring at a defined location. It normally provides electrical or digital measurements to a compatible data logger, controller or monitoring platform.

Such a sensor may be useful for observing environmental noise trends in industrial areas, urban installations or monitoring networks. Its suitability for formal acoustic compliance measurements depends on its documented measurement capabilities and required performance verification.

Personal Noise Dosimeter

A personal noise dosimeter is worn by a worker and measures noise exposure over time. It is generally more appropriate than a stationary area sensor when the objective is to assess the exposure of a person moving between different noise environments.

Dose calculations and time-weighted exposure assessments depend on the chosen measurement method and applicable occupational requirements.

What Do IEC 61672 Class 1 and Class 2 Mean?

IEC 61672-1 specifies electroacoustical performance requirements for sound level meters, including Class 1 and Class 2 instrument categories.

These categories define different permitted performance tolerances. Class 1 instruments have more stringent requirements in relevant parts of the specification than Class 2 instruments.

However, a product description referring to IEC 61672, an A-weighted measurement or factory calibration does not by itself establish verified Class 1 or Class 2 compliance.

For projects requiring compliance measurements, the instrument's documented standards conformity, calibration records, measurement functions and applicable verification requirements should be established before selection.

NiuBoL NBL-W-NS Noise Sensor for Continuous Monitoring

The NiuBoL NBL-W-NS Noise Sensor is a fixed measurement instrument designed to provide sound-level data for environmental and industrial monitoring applications.

The published NBL-W-NS manual identifies a condenser microphone, a 30–130 dB measurement range, a 31.5 Hz–8 kHz frequency range and an RS485 communication interface for the documented version.

The noise sensor can be connected to a compatible data logger, PLC or IoT gateway to collect measurements for local recording or remote environmental monitoring.

Its measurement and communication capabilities should be distinguished from those of a full-featured integrating sound level meter or occupational dosimeter. Projects requiring LAeq, LAFmax, peak measurements, octave-band analysis or formal acoustic compliance should specify those requirements before selecting an instrument.

Choosing the Right Device for Noise Measurement

The most useful selection question is not simply which device measures decibels, but what measurement must be obtained and how the result will be used.

Practical Noise Measurement Considerations

Sound-level measurements are affected by the measurement location, microphone orientation, nearby reflective surfaces, background noise and environmental conditions.

For outdoor monitoring, wind can create unwanted microphone noise. Suitable wind protection may be required. Instruments should also be installed and operated within their specified temperature and humidity limits.

Measurement duration and processing settings are particularly important when sound levels vary over time. Short spot measurements may not adequately describe intermittent traffic, machinery cycles or other changing noise sources.

For formal measurements, use the appropriate calibration, instrument settings, placement and reporting procedures required by the applicable measurement method.

Frequently Asked Questions About Noise Measurement

What device is used to measure noise?

A sound level meter is the most common instrument for measuring noise levels. Fixed noise sensors and personal dosimeters are used for continuous monitoring and individual exposure assessment respectively.

Is a decibel meter the same as a sound level meter?

The terms are often used interchangeably. However, the exact measurement functions, accuracy, weighting modes and standards conformity depend on the instrument rather than its informal name.

Can a noise sensor measure LAeq?

Only if the sensor or connected measurement system supports an appropriate equivalent continuous sound-level calculation. A basic sound-level output does not automatically establish LAeq capability.

Can a fixed noise sensor send measurements to a remote server?

Yes. A sensor with a compatible electrical output can connect to a data logger or IoT gateway, which transmits measurements using the available communication network and supported protocol.

Noise Sensor Instruction Manual

Technical specifications and communication details for the documented NBL-W-NS version are provided in the product instruction manual.

NBL-W-NS Noise Sensor Instruction Manual.pdf

Noise Monitoring with NiuBoL

NiuBoL provides fixed environmental noise sensors for integration into industrial and environmental monitoring systems.

For continuous monitoring projects, confirm the required sound-level indicators, measurement range, weighting functions, output interface, installation environment, receiving data logger and any applicable standards requirements before selecting the instrument.