What are the three standards for detecting automobile noise in China?

1. Sound pressure and sound pressure level: Through physical properties, we can know that noise includes sound pressure and sound pressure level, sound intensity and sound intensity level, sound power and sound power level. Sound pressure and sound pressure level mainly represent the intensity parameters of noise. The greater the sound pressure, the stronger the sound. But the range that people can hear is 2x 10-5 (hearing threshold sound pressure) ~20Pa (pain threshold sound pressure).

2. noise spectrum: the frequency of sound is also the cause of noise, and the frequency range that people can hear is 20~20000Hz. Spectrum is also one of the prescribed standards, and there is a corresponding matching diagram to let people know.

3. Noise level: Because people's ears have different recognition abilities for sounds with different frequencies, the evaluation of noise often adopts indicators suitable for people's physiological feelings. The change of sound pressure level is no longer determined by objective reasons, but also depends on hearing.