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Acoustic Transmission Loss Calculation

Parameters Material 1
Thickness (mm)
Density (kg/m3)
Young Modulus (MPa)
Damping Ratio (%)
Poisson Coefficient

Freq (Hz) R Calc (dB) R User (dB)


The calculation of the acoustic transmission loss is based mainly on the work of John Davy - Predicting the Sound Insulation of Walls - 2009
As proposed by Bies in "Engineering Noise Control Theory and Pratice - 2008", around the critical frequency, we use the Calculation from Shard (1973) is used.
Mainly, 3 zones are calculated :

  • For \( f < 0.8f_c \), the calculation is based on the mass law with \(f_c\) the critical frequency
  • For \(0.8fc < f < 1.2fc \), the transmission loss depends of the damping factor and the critical frequency
  • For \(1.2fc < f\), the transmission loss depends of the damping factor with an increasing of 9dB/octave

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