Datalogging sound level meters are very useful instruments

Each field has its own instrumentation such as medical instruments for doctors and hospitals, tools and machinery for construction crews and even chalk, blackboards and whiteboards for the teaching profession. In the field of noise pollution and noise control the most important piece of equipment is the sound level meter.

 

Area sound level meters are used to measure the noise levels in the area and you will find that digital sound level meters are very popular. Datalogging sound level meters have proved to be very useful instruments in the field and are widely used in many industries. A sound level meter (SLM) is a device used to make frequency-weighted sound pressure level measurements displayed in dB-SPL. 0.0 dB-SPL is the threshold of hearing, and is equal to 20uPa (microPascals). This correlates to what one would aurally perceive when in a deep cave or in a large anechoic chamber.

Packaged as a single-function handheld test device, sound level meters are intended to be held at arm’s length during measurements (to reduce the effects of the body on the measurements) or secured to a tripod stand for more stability. The SPL range switch provides a balance between minimizing the preamp noise level and measuring a wide range of sound pressure levels. Most of the commonly available sound level meters measure from about 30 to 130 dB-SPL and do this in 3-4 ranges.

Almost all sound level meters are designed and specified to perform to one of four internationally standardized levels of accuracy:

·         Class-0 SLMs are employed primarily to calibrate other SLMs and may be used for very high precision noise measurement in controlled spaces and/or for academic research.

·         Class-1 and Class-2 SLMs are most widely used by acousticians, sound system professionals, industrial designers/ manufacturers and researchers in academia and government. Measurements made with these levels of accuracy are generally acceptable as evidence in the resolution of legal disputes.

·         Class-3 SLMs are restricted to noise survey meters and dosimeters.

Sound level meter - datalogging/ recording

Datalogging sound level meters record data over time either with a built-in memory or through a connection to a memory storage device such as the hard-drive of a PC or an external logger. As a small, battery-powered, and portable device which can be mounted on a tripod and left unattended and even located outdoors, datalogging sound level meters, equipped with internal memory, allow measurements to be recorded internally at user-defined intervals. 

After a measurement session is completed, the datalogging SLM can be brought to a PC to transfer the stored readings. This allows the user to store files, view graphs, and make hard-copy reports.

Most area sound level meters have the same set of user adjustments, including SPL range selection, A and C weighting filters, slow and fast detector response, and minimum or maximum SPL. Although digital sound level meters are not difficult to use, it is still necessary that the person operating the sound level meter has some training and knows how to use the equipment properly and to be able to understand the results.

Noise measurement methods include the use of sound meters

Health and safety in the workplace are serious issues and noise pollution is just one of the things which need to be constantly monitored. This is done with the use of sound meters or sound level meters and is an essential part of protecting employees from the harmful effects of dangerous noise levels. 

Noise pollution is the disturbing or excessive noise that may harm the activity or balance of human or animal life. The source of most outdoor noise worldwide is mainly caused by machines and transportation systems, motor vehicles, aircraft, and trains. Outdoor noise is summarized by the word environmental noise. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential areas.

Measuring procedures

There are two basic approaches to measuring noise in the workplace:

·         The exposure of each worker, worker type or worker representative may be measured. The noise dosimeter is the preferable instrument for this purpose.

·         Noise levels may be measured in various areas, creating a noise map for the determination of risk areas. In this case, a sound level meter would be used to take readings at regular points in a coordinate network.

What is a sound level meter?

A sound level meter is a basic tool in measuring sound. A sound level meter or sound meter is an instrument that measures sound pressure level, commonly used in noise pollution studies for the quantification of different kinds of noise, especially for industrial, environmental and aircraft noise. However, the reading from a sound level meter does not correlate well to human-perceived loudness, which is better measured by a loudness meter. The current international standard that specifies sound level meter functionality and performance is the IEC 61672-1:2013.

What is a sound meter composed of?

Instruments for noise measurement include sound level meters, noise dosimeters and auxiliary equipment. The basic instrument is the sound level meter, an electronic instrument consisting of a microphone, an amplifier, various filters, a squaring device, an exponential averager and a read-out calibrated in decibels (dB).  

Sound level meters are categorized by their precision, ranging from the most precise (type 0) to the least (type 3). Type 0 is usually used in the laboratory, type 1 is used for other precision sound level measurements, type 2 is the general purpose meter, and type 3, the survey meter, is not recommended for industrial use. 

Nowadays, sound meters are becoming increasingly small and easy to use, while at the same time their measurement possibilities are expanding. For measuring non-steady noise exposures, such as those that occur in intermittent or impulse noise environments, an integrating sound level meter is most convenient to use. 

These sound level meters can simultaneously measure the equivalent, peak and maximum sound levels, and calculate, log and store several values automatically. It is important to make sure that noise measuring instruments are always properly calibrated. This means checking the instrument’s calibration acoustically before and after each day’s use, as well as making electronic assessments at appropriate intervals.