Sound Level Meter / Noise Level Meter
Sound level meter instruments and analyzers by Brüel & Kjær are designed for class 1 sound measurement, ease-of-use, and unrivaled flexibility. In fact, the latest generation of our sound level meters can be directly operated via smartphones, and with the addition of our specialized apps and processing software, our sound level meters provide the ideal measurement solution. It's been over 60 years since Brüel & Kjær invented the world's first portable sound level meter. And we still lead the industry today.
B&K 2245 Sound level Meter With Noise Partner
A complete class 1 sound / noise measuring solution for dedicated measurement applications. B&K 2245 is designed with task-tailored Noise Patrol Apps for specific measurement applications, providing you with the tools you need to get your job done.
B&K Type 2250 Or Type 2270 - Single or Dual Channel Measurements
With an award‐winning design and interface based on extensive research among technicians, engineers and consultants, our Type 2250 and Type 2270, come equipped to handle the most demanding measurement tasks.
CHOOSING YOUR SOUND LEVEL METER
WHAT IS A SOUND LEVEL METER
A sound level meter is a measuring instrument, designed to measure sound levels in a standardized way.
Commonly referred to as a sound meter, noise meter, decibel meter, or sound pressure level meter, a sound level meter is designed to respond to sound in approximately the same way as the human ear.
The purpose of a sound level meter is to give objective, reproducible measurements of sound pressure levels (SPL).
Sound level meters and analyzers are used to measure and manage noise from a variety of sources. They are often employed in environmental noise assessment from sound sources, such as industrial plants, road and rail traffic, and construction work.
In urban environments, noise pollution - or excessive noise exposure - directly affects the people who live and work in the affected areas. To ensure noise regulations are followed, noise is measured from a variety of sources as sports events, outdoor concerts, parks, and residential- or commercial neighbors. Each sound/noise source is defined by its own set of characteristics, which can pose challenges for the professionals assessing them.
Listed below are articles describing the most common applications:
- Room and building acoustics
- Sound power and noise source identification
- Assessing workplace noise and OHS evaluations
- Environmental noise measurements
HOW DOES A SOUND LEVEL METER WORK?
At its very core, a sound level meter basically consists of a microphone, a preamplifier, a signal processing unit, and a display.
The most suitable type of microphone for a sound level meter is a condenser microphone, which combines precision with measurement reliability. The microphone converts the sound signal to an equivalent electrical signal. The electrical signal produced by the microphone is at a very low level and must be enhanced by a preamplifier, before reaching the main processor.
Signal processing applies frequency weightings and time weightings to the signal, as specified by international standards such as IEC 61672 – 1, which a sound level meter complies with. The signal can also be available at output sockets in either AC or DC charge. The sockets are typically used in connection to external instruments or to connect with data acquisition systems to provide a record for further processing.
The analyzer applies Fast, Slow and Impulse (or ‘F’, ‘S’ and ‘I’) time weightings, which are the required weightings according to most international and national standards and guidelines. Environmental assessment standards usually specify which time weighting to use.
Leq / LAeq
An octave is a frequency band where the highest frequency is twice the lowest frequency. For example, an octave filter with a centre frequency of 1 kHz admits frequencies between 707 and 1414 Hz but rejects all others. (The name octave stems from the fact that an octave covers eight notes of the diatonic musical scale). A third octave covers a range where the highest frequency is 1.26 times the lowest frequency.
After the signal has been weighted and/or divided into frequency bands, the resultant signal is amplified, and the Root Mean Square (RMS) value determined in an RMS detector. The RMS is a special kind of mathematical average value. It is of importance in sound measurements because the RMS value is directly related to the amount of energy in the sound being measured.
IEC 61672-1 (international standard) defines frequency weightings A, C and Z, but other frequency weightings are occasionally used in specialized applications.
C-weighting is mainly used when assessing peak values of high sound pressure levels. It can also be used, for example, for entertainment noise measurements, where the transmission of bass noise can be a problem.
The standard is published in three parts:
- Part 1: Specifications: Requirements for sound level meter performance and functionality for class 1 and class 2 sound level meters
- Part 2: Pattern evaluation tests: Details of the tests necessary to verify conformance to all mandatory specifications given in IEC 61672-1. Used by test laboratories to ensure that instruments meet manufacturers claims.
- Part 3: Periodic tests: Procedures for periodic testing of sound level meters conforming to the class 1 or class 2 requirements of IEC 61672-1:2002
The standard is in two parts:
- Part 1 (2016): Basic quantities and assessment procedures
- Part 2 (2017): Determination of sound pressure levels