Investigation of noise. Noise Measuring Instruments

Sounds surround us everywhere - only in rare cases modern man can completely immerse himself in silence. In this connection, the value of regulation of noise parameters increases. In the workplace, for example, special requirements are imposed on the organization of working conditions. The list of such requirements necessarily includes optimal parameters of sound impact. However, noise research may be required in other situations - in a medical facility, in public places and, of course, at home. For this purpose use special devices - sound level meters. But first you have to deal with the very nature of sound.

Sources of sound

Most of the sources of urban noise are formed by anthropogenic sound generators. For example, road transport, air flows that pass between buildings, engineering systems, etc. Generally, the causes of noise of this kind are negative, since they are dominated by low frequencies, as well as a chaotic change of accents throughout the spectrum. This can be judged especially by the work of industrial enterprises and communication equipment.

Of course, the most favorable, in terms of acoustics, the situation is celebrated outside the city. In this case, nature itself is the source. One of the most soothing and relaxing is the sound of the sea, which is characterized by periodic and pronounced fluctuations. Slow and monotonous sound creates a unique and attractive sea rhythm, contributing to the strengthening of the nervous system.

Device devices

In today's market of sound level meters, digital instruments are popular today. They have small dimensions and a robust plastic housing, which is complemented by a microphone - however, this element can be integrated inside the device. The device also includes an amplifier, filter elements, an indicator and a detector. Actually, the human ear has many similar parts in terms of functionality. In turn, a special technique allows performing noise research with fixing several parameters simultaneously. Filters catch sounds with different frequencies, and information about the measurements taken is reflected on the screens in decibels. As for power supply, most sound level meters are powered by a battery, the charge of which can vary from 50 to 70 hours.

Principle of operation

As for the principle of operation, in this case it is more appropriate to compare the device with a microphone. The main difference will be that the sound level meter interacts during the measurement with a voltmeter, calibrated in decibels. Since the signal of the electric flow at the output from the microphone is equivalent to the initial noise, the addition in the level of acoustic pressure that acts on the membrane will cause a similar increase in the voltage when entering the voltmeter. On this principle, a noise measurement is constructed, the indicators of which are reflected on the display. To perform measurements of the sound pressure indicators , the signal is passed through special filters - this is done when it is on the path from the microphone to the voltmeter.

Since the ear's ability to perceive sound is determined not only by the frequency characteristics of the noise, but also by its intensity, several types of filtration elements are provided in the instruments. The choice of a particular device depends on the characteristics of the permissible noise at the measurement site. Filters make it possible to simulate the amplitude-frequency spectrum under conditions of a given noise power.

Technical and operational characteristics

Manufacturers strive to distinguish models designed solely for volume measurement, and apparatus for universal measurements. Nevertheless, the volume level remains one of the key characteristics of almost all sound level meters - this index varies from 30 to 130 dB. It is important to note one feature of noise meters. Some models, when working in conditions where the sound factor exceeds the maximum scale bar, do not perform noise research at all because of limitations of their capabilities. The next characteristic is the accuracy of the measurements. This quality is determined by the error, which can be from 1 to 1.5 dB. Accordingly, the smaller the deviation in the measurements of the sound level meter, the higher its accuracy. The operation of the instruments can be influenced by the temperature regime. For example, if you specify a range from 0 to 40 ° C, the machine can be used in an open area.

Manufacturers

In the market you can find devices from both specialized manufacturers of measuring equipment and products from well-known construction brands. The first category is the Testo model, which can be called the best in the class. They are characterized by a wide frequency range, capacious batteries and a large spectrum of measurements on decibels. However, the devices of this brand are the most expensive - an average of 20 to 30 thousand rubles. If you plan to study noise in the home, you can pay attention to the products of Geo-Fennel and ADA. First, the models of these manufacturers provide a good accuracy of measurements, and secondly, they are available at a price - on average such devices cost 3-4 thousand rubles.

Reviews about sound level meters

Users note the convenience of digital sound level meters. Most manufacturers offer devices with ergonomic bodies, as well as informative screens, which adds comfort in the process of work. The shortcomings of many devices of this type are attributed by the owners to the short operating time of the charger and serious errors. However, the last nuance in many respects depends on what sources of noise are subjected to research. In addition to the immediate function, it is also recommended to pay attention to the device's ability to operate in harsh external conditions. The presence of a body resistant to mechanical influences and moisture is unequivocally regarded as an advantage.

Conclusion

Even taking into account the use of modern technologies, the developers of measurement technology can not solve all the problems associated with the definition of sound indicators. However, for the majority of users existing offers are enough. For example, the noise of the sea provides frequency fluctuations on average from 31 to 20,000 Hz. To cover this spectrum today, it is not difficult to find a device from the middle segment. Another thing is that for highly specialized professional tasks, equipment may be required not only with extended ranges of basic operating parameters, but also with the possibility of performing additional measurement functions.