Acoustic sense let you with small eobd2 white said bye bye

Air in various voice, no matter what form they have, all is due to the vibration of the object caused by: knock drum when eobd2 you hear the drums, and at the same time, can feel the vibration of the raised; People can speak is due to the vibration of the vocal cords throat; Whistle, jet aircraft roar, because when the exhaust gas from the vibration. In a word, the vibration of the object is the root of produce sound, sound objects called source. The voice of the sound source must be through the intermediate medium to spread out, the people most familiar sound transmission medium is air, in addition to the gas, liquid and solid also can spread the voice. Vibration in the medium in the rate of spread that sound velocity, the velocity of sound in a medium depends on the medium elasticity and density, therefore, the voice in different medium propagation speed is different: in liquid and solid velocity of general than in the air much faster, for example in the water velocity for 1450 m/s, and in copper is for 5000 m/s. The propagation velocity of eobd2  sound in air with air temperature increases.

Push ahead with air vibration called acoustic, the sound waves space cry field. When the acoustic vibration in the air is known to travel time and space temperament point is not taken, it is just in the original position back and forth near the vibration, so the sound propagation is refers to the vibration transfer. If a body vibration amplitude with the change of time such as sine curve that, then the vibration called Jane harmonic oscillation, object to make the simple harmonic oscillation around when the air particle and Jane scrubbing vibration. Object to leave rest position distance says displacement χ, the biggest displacement that amplitude α, harmonic vibration displacement and the relationship between the eobd2   time expressed as χ = α sin (2 π ft + φ), including f for frequency, (2 π ft + φ) call Jane harmonic oscillation of a phase Angle, it is decided to object motion state of important physical quantity, amplitude α size determines the strength of the voice.

Objects in the number of vibrations per second is called frequency, the unit is Hertz (Hz). The number of vibrations per second, the more the frequency is high, the human ear hear the tip or the higher the tones. The human ear to all and not the frequency of vibration can feel. Generally speaking, the human ear can only hear frequency for 20 ~ 20000 hz voice, usually the frequency range of voice called audio sound. Less than 20 hz voices call infrasound, more than 20000 hz voice called ultrasonic. Time and ultrasonic sound the human ear can hear, but there are some animals but can hear, such as mouse can hear infrasound, bat can feel ultrasonic.

Sound waves in two adjacent compression OBD2 Scanner Code zone or expansion area known as the distance between the wavelength λ, the unit is m (m). Wavelength is sound in a period of time in the distance of travel. The wavelength and frequency is inversely proportional, the higher the frequency, the shorter the wavelength; Frequency is low, the long wavelength.