貨運百科

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標題:

噪音計算公式

發問:

機器沒開機時是66分貝，開機後為80分貝，能否估算出機器在實驗室環境50分貝時,開機後的噪音值?

最佳解答:

The Sound Pressure Level: Lp=10 log( p2 / pref2 )=10 log( p/pref )^2 = 20 log(p/pref ) where Lp = sound pressure level (dB) p = sound pressure (Pa) pref = 2x 10-5 - reference sound pressure (Pa) let sound pressure level : Lpm = sound pressure of machine, , Lpb1 = sound pressure of background 1, , Lpb2 = sound pressure of background 2, sound pressure: pm - machine, pb1 - background 1, pb2 - background 2, 環境一: Lpm-Lpb1=14 dB = 20 log (pm/pb1) (Equation 1) Lpb1 = 66 = 20 log (pb1/pref) pb1 = 39.9 x 10^-3 Pa put into Eq.1, 14 = 20 log (pm / 0.0399) pm ~ 200 x 10^-3 Pa 環境二: Lpb2 = 50 = 20 log( pb2/pref ) pb2 = 6.3 x 10^-3 Pa now, operate the machine in situation 2, Lpm-Lpb2 = 20 log (pm/ pb2) Lpm - Lpb2 = 30 dB so, Lpm = 30 + 50 = 80 dB 機器在實驗室環境50分貝時,開機後是80分貝

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