Tables 1 and 2 provide the coefficients for Equation 4 at each 1/3 octave frequency band from 50 to 10,000 Hz for the 1 in.
is the average difference between the measured value and the predicted value at each 1/3 octave frequency band. Similarly, Std.
A linear regression was performed on the data for each duct diameter D to develop an equation relating IL to L in ft (meters) at each 1/3
octave frequency band. This resulted in 120 linear equations, each with L as the independent variable for 1 in.
The estimated weaker shielding effect of the "L90" type barrier in the studied 1/3
octave frequency bands might be interpreted using the results of the calculations carried out by the Chinese researchers Xintan et al.