Acousti-Ply ACOUSTICAL GUIDE
 
AC 118 - RESULTS OF MEASUREMENT OF THE SOUND
ABSORPTION COEFFICIENT
(ALPHA) BY THE REVEBERATION METHOD
 
Conducted by CSIRO - DIVISION OF BUILDING RESEARCH
 
The following test data is based on 7 mm thick 5 ply having 10.7mm round holes providing
a 21% perforation. The lining was fixed over nom 50mm thick insulation of apx 57kg/m³
 
1/3 Octave
Band
(Hz)
  
 
Mean R. T.
Bare Room
(S)
  
 
95% Confidence
Interval
on Alpha (+-)
  
Measured value
of absorption
coefficient
(Alpha)
100   9.14   0.08   0.20
125   8.93   0.06   0.30
160   7.30   0.04   0.44
200   7.31   0.06   0.56
250   6.80   0.11   0.80
315   7.15   0.04   1.00
400   6.68   0.04   1.03
500   6.63   0.06   1.09
630   6.61   0.03   1.06
800   6.17   0.03   1.02
1000   5.67   0.01   0.97
1250   5.28   0.01   0.94
1600   4.62   0.03   0.90
2000   3.99   0.03   0.85
2500   3.49   0.02   0.75
3150   3.13   0.02   0.64
4000   2.69   0.03   0.58
5000   2.27   0.01   0.54

 

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