Why shop car pads? What is the role?

Many owners have a misconception, that shop car pad is clean. In fact, auto shop pad is mainly noise, reduce and reduce driver fatigue, relieve tinnitus. Short audio sound frequency, a vibrating object, the vibration frequency of the number of vibrations per second for the objects, unit of frequency in hertz. Generally, humans are able to hear the sound vibrations at frequencies between 20 Hz to 20,000 Hz. Sound wave vibration source called the sound source. Less than 20 Hz and 20,000 Hz, respectively, within the scope of infrasound and ultrasound, the human ear can not hear. In the sonic range, with increasing frequency pitch from low to high, but at different frequencies, the human ear is not consistent sensibility. Under normal circumstances, the audio in 1000 Hz or less, with the frequency decreases, hearing will gradually slow, therefore, the human ear to low frequency noise is relatively easy to bear, and to feel more acutely the high frequency noise, poor tolerance. If long-term living in high frequency loud environments, with time and age can cause tinnitus or profoundly deaf ear part. So I chose cars pads to protect motorists and passengers health is necessary. http://www.btsfqczs.com