Correct measurement method for noise meters
When measuring the noise meter, the instrument should choose the correct gear according to the situation, hold both sides of the noise meter with both hands flat, and point the microphone towards the measured sound source. Extension cables and rods can also be used to reduce the impact of the noise meter appearance and human body on the measurement. The position of the microphone should be determined according to relevant regulations.
The sound level meter used for measuring noise in a noise machine can be divided into four types based on sensitivity:
(1) Slow. The time constant of the meter head is 1000 ms, usually used for measuring steady-state noise, and the measured value is the effective value.
(2) Quick. The time constant of the meter head is 125ms, which is generally used to measure unstable noise and transportation noise with significant fluctuations. The fast gear approaches the human ear's response to sound.
(3) Pulse or pulse hold. The rise time of the watch needle is 35ms, used to measure pulse noise with a longer duration, such as punching machines, press hammers, etc. The measured value is the maximum effective value.
(4) Peak Hold. The rising time of the watch needle is less than 20ms. It is used to measure pulse sounds with a short duration, such as guns, guns, and explosions. The measured value is the peak value. That is the maximum value. Distance measuring instrument, height measuring instrument, laser projection instrument, flow meter, GPS thickness measuring instrument, level gauge, flat meter, waveform recorder, testing fixture, voltage and current recorder, data collector, graphic recorder, flow integrating instrument
The sound level meter can be connected to an external filter and recorder for spectral analysis of noise. The domestically produced ND2 precision sound level meter is equipped with an octave bandpass filter, which is easy to carry to the site and perform spectral analysis. Process calibrator, temperature calibrator, pressure calibrator, circuit calibrator, calibration buffer, clamp meter corrector, oscilloscope calibrator, noise meter corrector, current corrector, multifunctional corrector, humidity corrector, pH corrector
Noise control measures based on acoustic principles: In addition to the above methods for reducing noise, acoustic control methods can also be used to reduce noise, mainly including sound absorption, sound insulation, shock absorption, sealing, etc. For car noise control, the components that cause noise, such as the engine, exhaust pipes, and tires, are finalized at the time of vehicle delivery. Therefore, the design level and assembly process of each component determine the level of noise, and also reflect the technical level and technological content of a car. The sound insulation of calm cars is mainly developed by controlling and blocking the transmission path.
