What should be taken into account when timing sound level?
The sound level meter is composed of a microphone, an attenuator, a weighting network, an amplifier, a detection network and an indicator. It is an instrument that measures the sound pressure level and sound level according to a certain frequency weighting and time weighting. It is the most commonly used instrument in acoustic measurement. It can measure the noise level of industrial noise, traffic noise, environmental noise and living noise, etc. according to the auditory characteristics of human ears.
Factors to consider when choosing a sound level meter:
Price: When purchasing a sound level meter, you first need to consider the price range of the product. The price of a sound level meter depends on many factors, including features, accuracy class, number of channels, storage capacity, and more. Generally speaking, domestic sound level meters with the same indicators are much cheaper than imported products.
Function: For the sound level meter, the measurement function is the most important index, which not only determines the application range of the sound level meter, but also has the greatest relationship with the price of the sound level meter. According to the type of the signal to be measured, for steady-state noise signals, the function of the sound level meter is only to measure the instantaneous sound pressure level; for the measurement of unsteady-state signals, it is generally required to measure the time-average sound level or the equivalent sound level; For spectrum analysis, a noise spectrum analyzer should be selected.
Number of channels: A general sound level meter has only one channel, and only one channel of sound pressure level is measured. Sometimes it is necessary to measure multi-channel sound pressure levels, so it is necessary to use multiple channels. For example, two channels are required to measure sound intensity levels, and more channels are required to measure sound power levels. Multi-channel sound level meters greatly expand the use of sound level meters.
Accuracy class: Accuracy class of sound level meter: Class 1 and Class 2.
Spectrum analysis function: In order to perform spectrum analysis on noise, it is necessary to select the spectrum analysis function. Octave and 1/3 octave spectrum analysis are the most widely used in acoustic measurement. In the past, spectrum analysis was realized using analog filters, but now most of them use digital technology, and real-time spectrum analysis is carried out through digital filters.
Measuring range: The measuring range of the sound level meter sometimes needs to consider its measurement upper limit in order to measure high sound pressure levels, such as 140dB, or even above 160dB; sometimes it needs to consider its measurement lower limit in order to measure low sound pressure levels, such as below 20dB ; Usually the measurement range of the sound level meter is in the range of 25dB to 130dB.
Interface: The current sound level meter generally has RS232, USB and other interfaces, which are used to connect to a micro-printer or computer, and users can choose according to the test needs.
Calibration: The sound level meter needs to use a sound calibrator for sound calibration during use. The sound calibrator is often used as a supporting instrument for the sound level meter and becomes an integral part of the sound level meter. There are two types of sound calibrator: piston sounder and sound level calibrator. The piston sounder produces 250Hz, 124dB sound pressure level, and the accuracy level is 1 or 0; the sound level calibrator produces 1000Hz, 94dB sound pressure level, and the accuracy is The grade is either level 2 or level 1. A level 1 sound level meter needs to be calibrated with a level 1 or level 0 sound calibrator, and a level 2 sound level meter needs to be calibrated with a level 2 or level 1 sound calibrator.
