When buying a car, the sales consultant usually mentions the mute effect of the car, and most car advertisements also publicize that "XX car has undergone dozens of nhv upgrades, which can bring a quiet ride feeling".

NVH可以說是一個汽車專業術語，它是“Noise Vibration Harshness”的縮寫，即噪聲、振動、聲振粗糙度。

NVH can be said to be an automobile professional term, which is the abbreviation of "noise vibration harshness", that is, noise, vibration and sound vibration roughness.

之所以在工程領域總是將震動與噪聲綜合在一起講，是因為聲音總是伴隨著震動而來。聲音是由物體震動而產生的聲波，并通過媒介（固體、液體或氣體等，比如鋼鐵、水和空氣）傳播。而人耳能聽得到的聲波范圍在20Hz-20kHz，低于或者高于這個范圍的聲波，人耳都是無法識別出來的。

The reason why vibration and noise are always combined in the engineering field is that sound always comes with vibration. Sound is a sound wave generated by the vibration of an object and transmitted through a medium (solid, liquid or gas, such as steel, water and air). The range of sound waves that can be heard by the human ear is 20Hz-20KHz. The human ear cannot recognize the sound waves lower or higher than this range.

優美的旋律音樂會讓人心情舒暢，相反的人要是長期在吵雜的噪音中會帶來很多負面影響。醫學家研究發現，噪音會嚴重影響人們的睡眠質量，并會導致頭暈、頭痛、失眠、多夢、記憶力減退、注意力不集中等神經衰弱癥狀和惡心、欲吐、胃痛、腹脹、食欲呆滯等消化道癥狀。它還有害于人的心血管系統，我國對城市噪音與居民健康的調查表明，環境噪音每上升一分貝, 高血壓發病率就增加3%。

The beautiful melody concert makes people feel comfortable. On the contrary, if people are in the noisy noise for a long time, it will bring a lot of negative effects. Medical experts have found that noise will seriously affect people's sleep quality, and lead to neurasthenia symptoms such as dizziness, headache, insomnia, dreaminess, memory loss and inattention, as well as gastrointestinal symptoms such as nausea, vomiting, stomach pain, abdominal distension and dull appetite. It also has a harmful effect on the cardiovascular system of people. Our survey of city noise and residents' health shows that the incidence rate of hypertension increases by 3% per environmental noise.

所以，足夠安靜的駕乘環境才會帶來更舒適的乘坐體驗。也因此，如今不論是高檔豪華轎車還是普通家用轎車，都在強調車內噪音大小。但是，車內真是越安靜越好嗎？

Therefore, a sufficiently quiet driving environment will bring a more comfortable riding experience. Therefore, nowadays, both high-end luxury cars and ordinary family cars are emphasizing the noise level in the car. But is it true that the quieter the car, the better?

其實，在很多汽車工程師看來并非如此。

In fact, many automotive engineers do not think so.

首先，人們不能試圖徹底消除噪聲和振動。

First of all, people try to eliminate noise and vibration completely.

我們知道，汽車的動力源于發動機，并更終傳遞到車輪上，輪胎克服路面摩擦從而推動汽車前進。

We know that the power of the car comes from the engine and is finally transmitted to the wheels. The tires overcome the friction on the road and push the car forward.

所以，一輛汽車的振動來源就有很多，不僅有發動機、變速箱等運轉產生的振動，也有輪胎與路面摩擦、經過坑洼路面時產生的振動，而這些振動都將產生噪音。此外，還有風噪、零部件之間的碰撞、空調出風口、電路的電流聲等，都是一輛車的噪音來源。

Therefore, there are many sources of vibration of a car, not only the vibration generated by the operation of the engine and gearbox, but also the vibration generated by the friction between the tire and the road and when passing through the pothole Road, and these vibrations will produce noise. In addition, there are wind noise, collision between parts, air conditioning outlets, current sound of circuits, etc., which are all the noise sources of a car.

其次，駕駛員所需要的很多反饋都來源于噪音和振動。

Secondly, much of the feedback that drivers need comes from noise and vibration.

在開車的過程中，駕駛員需要收集各種路況反饋信息，這些信息的主要形式無外乎聲音，振動，視覺信息三類。而徹底消音就意味著駕駛員聽不到其他車的鳴笛聲、發動機或變速箱產生的異響聲、輪胎虧氣造成的摩擦聲、輪胎與地面接觸產生的沖擊聲。而路面振動又會通過轉向系統回饋到駕駛員的手上，駕駛員除了會感受到這些振動，它們產生的聲波也會傳遞到駕駛員的耳朵里。

In the process of driving, drivers need to collect various road condition feedback information. The main forms of this information are sound, vibration and visual information. Complete silencing means that the driver cannot hear the whistle of other vehicles, the abnormal sound generated by the engine or gearbox, the friction sound caused by tire air loss, and the impact sound caused by tire contact with the ground. The road vibration will be fed back to the driver's hand through the steering system. In addition to feeling these vibrations, the sound waves generated by them will also be transmitted to the driver's ears.

同時，路感對駕駛員也很重要。假如振動徹底被抑制，方向盤沒有把路面信息反饋給駕駛員，汽車的駕駛品質也就無從談起了。

At the same time, the road feel is also very important to the driver. If the vibration is completely suppressed and the steering wheel does not feed back the road information to the driver, the driving quality of the car will be out of the question.

此外，噪聲振動品質過分的好，風噪胎噪抑制的過分的好，會讓人喪失對車速的感覺。如果你開車到200km/h以上時，還像你坐在家里沙發一樣安靜，會讓人在充分安逸的狀態下開車，此時很可能就不認為自己在超速，而時間久了還會讓人犯困，這就是一種極度危險的狀態了。

In addition, if the quality of noise and vibration is too good, and the suppression of wind noise and tire noise is too good, people will lose the feeling of speed. If you drive more than 200km / h and are as quiet as you are sitting on the sofa at home, it will make people drive in a fully comfortable state. At this time, you may not think you are speeding, and it will make people sleepy after a long time. This is an extremely dangerous state.

，太過分的安靜也會讓人感到壓抑。

Finally, too much silence can also make people feel depressed.

俗話說“沉默是金”，但如果人待在過分安靜的環境里，卻會讓人無法忍受。

As the saying goes, "silence is golden", but if people stay in an excessively quiet environment, it will be unbearable.

美國一間“消音室”的建造者奧菲爾德說：“在安靜的環境下，耳朵會逐漸適應。屋子里越安靜，耳朵聽到的東西越多。你會聽到心臟的跳動，甚至可以聽到你的肺和胃發出咕嚕聲。在消音室，你自己變成了噪音。”他說，在這種靜室中，很容易令人迷失方向，時間久了還會令人產生幻覺。

"In a quiet environment, the ear will gradually adapt. The quieter the room is, the more things the ear hears. You will hear the beating of your heart and even the grunting of your lungs and stomach. In the anechoic room, you become noise." He said that in this kind of quiet room, it is easy to lose direction and hallucinate over time.