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