In order to simplify the question, the equivalent parameters method is used to the analysis of acoustic reactance. We use the effective acoustic compliance [DELTA][C.sub.r] representing the quantity of the inertia and elasticity of SHS which is connected in parallel with [C.sub.A] as shown in Figure 2(b).
Figure 16(b) shows that the specific acoustic reactance decreases slightly with the pore area fractal dimension in low-frequency range but increases in high-frequency range.
Furthermore, the larger the porosity, the smaller the acoustic resistance and the acoustic reactance. Therefore, the sound absorption coefficient decreases with the pore area fractal dimension when the frequency is lower than 2500 Hz.