# 14: Acoustics of Buildings and Acoustic Quieting¶

## Example number 1, Page number 14.18¶

In [4]:
#importing modules
import math
from __future__ import division

#Variable declaration
V=2265;      #volume(m**3)
a=92.9;      #absorption(m**2)

#Calculation
T=0.16*V/a;    #reverbration time(s)
T2=T/2;        #reverbration time when audience fill the hall(s)

#Result
print "reverbration time is",round(T,1),"s"
print "reverbration time when audience fill the hall is",round(T2,2),"s"
print "reverbration time is reduced to one-half"

reverbration time is 3.9 s
reverbration time when audience fill the hall is 1.95 s
reverbration time is reduced to one-half


## Example number 2, Page number 14.18¶

In [7]:
#importing modules
import math
from __future__ import division

#Variable declaration
V=12*30*6;    #volume(m**3)
A1=450;       #area of plastered wall(m**2)
a1=0.03;      #coefficient of absorption(m**2)
A2=360;       #area of wooden floor(m**2)
a2=0.06;      #coefficient of absorption(m**2)
A3=24;        #area of glass(m**2)
a3=0.25;      #coefficient of absorption(m**2)
A4=600;       #area of seats(m**2)
a4=0.3;       #coefficient of absorption(m**2)
A5=500;       #area of hall with audience(m**2)
a5=0.43;      #coefficient of absorption(m**2)

#Calculation
A=(A1*a1)+(A2*a2)+(A3*a3)+(A4*a4)+(A5*a5);    #total absorption(m**2)
Ae=A-(A5*a5);                                 #absorption when hall is empty(m**2)
T=0.16*V/A;   #reverbration time(second)
Te=0.16*V/Ae; #reverbration time when hall is empty(second)

#Result
print "reverbration time is",round(T,1),"second"
print "reverbration time when hall is empty is",round(Te,1),"second"

reverbration time is 0.8 second
reverbration time when hall is empty is 1.6 second


## Example number 3, Page number 14.19¶

In [11]:
#importing modules
import math
from __future__ import division

#Variable declaration
V=7500;    #volume(m**3)
T=1.2;     #reverbration time(second)

#Calculation
A=0.16*V/T;     #total absorption(OWU)

#Result
print "total absorption is",int(A),"m**2 or OWU"

total absorption is 1000 m**2 or OWU


## Example number 4, Page number 14.19¶

In [29]:
#importing modules
import math
from __future__ import division

#Variable declaration
V=12*10**4;      #volume(m**3)
a=13200;         #absorption(m**2)

#Calculation
T1=0.16*V/a;    #reverbration time(s)
T2=T1/2;         #reverbration time when audience fill the hall(s)
T=T1-T2;        #change in reverbration time(second)

#Result
print "change in reverbration time is",round(T,3),"second"

change in reverbration time is 0.727 second