By the spherical wave attenuation formula Lp=Lw-K+DIm-Ae
Lp=Lw-K+DIm-Ae
(1)Radiation is a spherical wave, the dispersion attenuation K:
K=10log(10,4π)+20log(10,r)
Which r is the distance between the two positions of a, b. The sound waves are not applicable to the approximation of plane wave.
(2)Directivity factor DIm: Whether there is a reflective surface near the source (ground is considered separately), or the source itself is not a point source. Adding a reflective surface is an increase of 3dB.
(3)Other additional attenuation Ae
Air absorption: Aa (related to frequency, air pressure, temperature, humidity)
At 20℃: Aao=7.4×10^(-8)f^2 r/H dB
Aa(T)=Aao/[1+4×10^(-6)△T f ]
Where H: relative humidity of air;
f: sound frequency.
Obstacle additional attenuation: Abhp (this is generally check the table)
Empirical formula: Af = 0.01d f^(1/3)
Meteorological additional attenuation Am
Mainly wind speed and temperature gradient, check the table to get the specific effect.
In this example, only the effect of K is considered
The result is Lp=Lw-K
Xiaoming hears about 130dB
The following is a discussion of the relationship between the intensity of the sound and the level of anger, the first step is to define the level of anger
Take the binary discrete distribution model
Let the individual may perform two kinds of behaviors: the angry behavior Q+ and the not angry behavior Q-, and
The individual may perform the angry behavior Q+ and the not angry behavior Q-, and
There are two types of behaviors. Behavior Q-, and
F(Q+) = G (1.1)
then we have
F(Q-) = 1-G (1.2)
G can be used as a measure of anger
When I've taken my pills, I'll come back to this nonsense in a serious way