In the present work, the acoustical excess attenuation of mixed grounds was measured in an anechoic chamber. The mixed grounds consisted of compressed wood to represent a hard ground state and a urethane foam to represent a soft ground state. To accou...
In the present work, the acoustical excess attenuation of mixed grounds was measured in an anechoic chamber. The mixed grounds consisted of compressed wood to represent a hard ground state and a urethane foam to represent a soft ground state. To account for the measured frequency spectra of the excess attenuation, we tested the De Jong and the Fresnel- zone models. A reasonable agreements were found in the low frequency range with the Fresnel zone model and in the high frequecny range with the De Jong model. Both models produced acceptable, but not satisfactory results. Therefore, a coupling model properly combining the two models is needed. On the otherhand, the predicted excess attenuations, obtained by treating a mixed ground as a uniform ground
disagreed with the measured ones.