Sounds surround us everywhere - only in rare cases can a modern person be completely immersed in silence. In this regard, the value of regulation of noise parameters is increasing. At workplaces, for example, special requirements are made for the organization of working conditions. The list of such requirements certainly includes optimal indicators of sound exposure. However, noise research may be required in other situations - in a medical facility, in public places and, of course, at home. For this purpose, special devices are used - sound level meters. But first, it’s worth understanding the nature of sound.
Sound sources
Most of the sources of urban noise are generated by anthropogenic sound generators. For example, motor vehicles, air flows that pass between buildings, engineering systems, etc. As a rule, the causes of this kind of noise are negative, since they are dominated by low frequencies, as well as a chaotic change of emphasis throughout the spectrum. This can be judged especially by the work of industrial enterprises and communication equipment.
Of course, the most favorable, from the point of view of acoustics, situation is noted outside the city. In this case, the source is nature itself. One of the most calming 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 marine rhythm that helps strengthen the nervous system.
Device device
In the modern market of sound level meters, digital devices are popular today. They are small in size and have a robust plastic case, which is complemented by a microphone - however, this element can be integrated into the device. The device also includes an amplifier, filter elements, an indicator and a detector. Actually, the human ear has many parts that are similar in functionality. In turn, a special technique allows you to perform noise research with fixing several parameters simultaneously. Filters pick up sounds with different frequencies, and information about the measurements taken is reflected on screens in decibels. As for the power supply, most sound level meters operate on battery power, 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 measurement with a voltmeter calibrated in decibels. Since the signal of the electric flux at the microphone output 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 voltage when it enters the voltmeter. On this principle, the measurement of noise is built, the indicators of which are reflected on the display. To perform measurements of sound pressure indicators , the signal is passed through special filters - this is done at the moment when it is on the way from the microphone to the voltmeter.
Since the ability of the ear to perceive sound is determined not only by the frequency properties of noise, but also by its intensity, several types of filtering elements are provided in the devices. The choice of a particular device depends on the characteristics of the permissible noise in the measurement area. Filters make it possible to simulate the amplitude-frequency spectrum under conditions of a given noise power.
Technical and operational characteristics
Manufacturers seek to distinguish between models designed solely for measuring volume and apparatus for universal measurements. Nevertheless, the volume level remains one of the key characteristics of almost all sound level meters - this indicator 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 coefficient exceeds the maximum scale bar, do not perform noise research at all because of the 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 devices may be affected by temperature conditions. For example, if you specify a range from 0 to 40 ° C, then the device can be used in open areas.
Manufacturers
On the market you can find devices from specialized manufacturers of measuring equipment, as well as products from well-known construction brands. The first category should include Testo models, which can be called the best in the class. They differ in a wide frequency range, capacious batteries and a wide range of measurements in decibels. However, devices of this brand are the most expensive - an average of 20 to 30 thousand rubles. If you plan to study noise in the domestic environment, you can pay attention to the products of Geo-Fennel and ADA. Firstly, the models of these manufacturers provide good accuracy of measurements, and secondly, they are affordable - on average, such devices cost 3-4 thousand rubles.
Reviews of sound level meters
Users note the ease of use of digital sound level meters. Most manufacturers offer devices with ergonomic cases, as well as informative screens, which adds comfort in the process. The disadvantages of many devices of this type, the owners include a short battery life and serious errors. However, the last nuance in many respects also depends on which noise sources are studied. In addition to the direct function, it is also recommended to pay attention to the ability of the device to operate in harsh environmental conditions. The presence of a body resistant to mechanical stress and moisture is clearly regarded as an advantage.
Conclusion
Even taking into account the use of modern technologies, the developers of measuring equipment can solve far from all the problems associated with determining sound performance. True, for most 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 ability to perform additional measurement functions.