In recent years, a negative impact of infrasound and ultrasound on human health has been observed and documented. Various factors, such as traffic, industry, and environmental influences, also contribute to noise in vehicles, therefore, precise measurement of low-frequency sound has become crucial due to excessive noise pollution. Since there are few recommendations and safety standards for regulating this area, the automotive industry has started using NVH (Noise, Vibration, and Harshness) standards, which are not yet complete. Hence, researching the impact of ultrasound and infrasound on humans is highly important and necessary. More attention is being paid to understanding the effects of low-frequency noise, measured with a sound level analyzer and meter.
Due to high noise exposure in traffic, an analysis of noise measurements in the passenger cabin was conducted, with a focus on the low-frequency range, both with closed and open windows.
In the first part of the assignment, acoustics is briefly described, including how sound is categorized, its impact on humans and their hearing range, sources of noise, and the standards used to address noise issues in the environment and the automotive industry.
In the second part, noise measurements were conducted in the passenger cabin while driving, using a measurement microphone connected to a Class 1 sound level meter. Data processing was carried out using the commercial software LabVIEW and the freely accessible program REW.
The obtained results indicate sound pressure levels ranging from 100 dB to 110 dB with closed windows and from 105 dB to 115 dB with open windows.
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