Propagation of spherical waves above ground

Abstract A new methodology is developed for the problem of sound propagation above ground. The respective advantages of pure tones generated by a pressure driver with a λ 4 tube and impulsive noises issued from an 8 mm alarm pistol with a double cavity absorbing silencer, are analysed. Use is made of minimum phase linear systems for which the modulus and phase of the transfer function are related by an Hilbert transform. Finally, the different parameters of a locally reacting model are calculated using a non-linear fitting procedure and the specific impedance values of the tested ground are estimated from the attenuations experimentally measured under grazing or oblique incidence.