What is the normal noise level inside a car?
2 Answers
The normal noise level inside a car is generally below 60 decibels. Here is some extended information on solving excessive car noise: 1. Engine noise: In addition to the mechanical sounds emitted by the engine body, it also includes intake system noise, which occurs when high-speed gas passes through the air filter, intake pipe, and valve into the cylinder, generating strong aerodynamic noise during the flow process. Engine noise mainly enters the cabin through the firewall and the front floor area of the driver's compartment. 2. Tire noise: Generally, tire noise consists of three main components: first, the air noise caused by the airflow in the tread gaps and the disturbance of air around the tire; second, the vibration noise caused by the tire body and tread vibrations; third, the road noise caused by uneven road surfaces. 3. Air noise: First, wind noise, which is caused by the separation of airflow around the car body leading to pressure changes; second, wind leakage or suction noise, which is caused by the interaction between air entering through gaps in the driver's compartment and body and the surrounding airflow; third, other noises, including cavity resonance. 4. Body structure noise: This is mainly influenced by two factors: first, the vibration transmission method of the body structure; second, the noise generated by the vibration of metal components in the body under internal and external forces.
With over 20 years of driving experience, I've encountered various noise changes. Normal in-car noise typically ranges between 50 to 70 decibels – engine idling at about 50 dB when stationary, 50-60 dB during city driving, and reaching 65-75 dB on highways. Influencing factors include speed and window status: wind noise increases significantly above 80 km/h, while opening windows immediately raises noise by 10 dB. Road conditions matter too – gravel roads can be 5+ dB louder than asphalt. Vehicle types differ greatly: older cars or SUVs may have higher noise levels, while luxury sedans or EVs with superior sound insulation can maintain around 50 dB. Personally, I find below 70 dB tolerable, but beyond that becomes distracting. Worn tires or aging bearings can elevate noise; regular maintenance checks or adding soundproofing materials (reducing noise by 5-10 dB) enhance comfort. Routine care like installing quiet tires and quality engine oil also minimizes abnormal sounds.
