Factors to consider when selecting a sound level meter
Sound level meter is a kind of instrument to measure sound pressure level and sound level according to certain frequency weighting and time weighting. It is the most commonly used instrument in acoustic measurements, can be industrial noise, traffic noise, environmental noise and living noise, etc., according to the human ear hearing characteristics of the approximate determination of its noise level instrument.
Sound level meter can be applied to environmental noise, electromechanical product noise, traffic noise, building acoustics and electroacoustics measurements. Some sound level meters can also be used to measure vibration by replacing the receiver section. The external connection or internal setting of octave filter or 1/3-octave filter of the sound level meter can be used to analyze the spectrum of noise.
With the development of electronic technology, especially large-scale integrated circuits and computer technology, the sound level meter in the frequency counting, detector and filter circuits through digital signal processing technology instead of analog circuits to achieve. This not only makes the circuit more simplified, wider dynamic range, but also greatly improve the function and stability, especially can realize the real-time spectrum analysis, so that the sound level meter is more widely used.
The sound level meter consists of microphone, attenuator, weighting network, amplifier, wave detection network and indicator. The foremost part of the sound level meter is the microphone, which converts the sound energy into electrical energy and sends it to the preamplifier of the host computer, amplifies it and sends it to the attenuator and the weighting network, and then finally displays the sound level reading through the detector and the indicator table with certain damping characteristics.
Factors to consider when choosing a sound level meter:
Price: The first thing you need to consider when shopping for a sound level meter is the price range of the product. The price of sound level meter depends on many factors, including functions, accuracy level, number of channels, storage capacity and so on. In general, the same indicators of the sound level meter, domestic than imported products are much cheaper.
Function: For sound level meter, measurement function is the most important index, which not only determines the application range of sound level meter, but also has the most relationship with the price of sound level meter. According to the type of signal being measured, for the steady state noise signal, the sound level meter function as long as the measurement of instantaneous sound pressure level; for the measurement of non-steady state signals, generally require the measurement of time-averaged sound level or called the equivalent sound level; for the need for spectral analysis, it is necessary to choose the noise spectrum analyzer.
Number of channels: The general sound level meter has only 1 channel to measure only 1 road sound pressure level. Sometimes you need to measure more than one sound pressure level, you need to choose more channels, for example, measuring the sound intensity level requires 2 channels, measuring the sound power level requires more channels, multi-channel sound level meter greatly extends the use of the sound level meter.
Accuracy level: Accuracy level of sound level meter: level 1 and level 2.
Spectrum analysis function: In order to perform spectrum analysis of noise, it is necessary to select the spectrum analysis function. Octave and 1/3-octave spectrum analysis are most often used in acoustic measurements. Previously, spectrum analysis was realized using analog filters, but nowadays, most of them use digital technology, and real-time spectrum analysis is carried out through digital filters.
Measurement range: The measurement range of sound level meter should sometimes consider its upper limit in order to measure the high sound pressure level, such as 140dB, or even to 160dB or more; sometimes it should consider its lower limit in order to measure the low sound pressure level, such as 20dB or less; usually, the measurement range of the sound level meter is within the range of 25dB to 130dB.
Interface: The current sound level meter usually contains RS232, USB and other interfaces for connecting to a micro printer or computer, which can be selected by the user according to the testing needs.
Calibration: Sound level meter needs to use sound calibrator for sound calibration in the process of using, the sound calibrator is often used as the supporting instrument of the sound level meter, which becomes an integral part of the sound level meter. There are two kinds of sound calibrators: piston sound generator and sound level calibrator, the piston sound generator produces 250Hz, 124dB sound pressure level, the accuracy level is 1 or 0; the sound level calibrator produces 1000Hz, 94dB sound pressure level, the accuracy level is 2 or 1. 1 level sound level meter needs to be calibrated by 1 or 0 sound calibrator, and 2 level sound level meter needs to be calibrated by 2 or 1 level sound calibrator.
