We put forward an efficient method for computing the input impedance of complex asymmetrically branching duct networks, and apply this method to simulation of the dynamic response of the lungs of normal adult humans in the frequency range extending to 10,000 Hz. The results indicate that the response of comparable symmetric and asymmetric branching networks differ at high frequency (> 2 kHz in air), and that the airway wall response is an important factor in determining system damping and resonant frequencies.