What type of soil transmits the best noise?

• A. Clay soils
• B. Sandy soils
• C. Gravel soils
• D. Loamy soils

Answer: (B)

The ability of soil to carry noise depends on how the soil’s stiffness, density, and damping affect acoustic wave movement. Dry sandy soils are relatively stiff and have strong grain-to-grain contacts with low internal damping, so compressional waves can travel through with less energy loss. That makes noise propagate more readily. In contrast, clay soils are cohesive and often moisture-rich, which increases damping and energy dissipation, reducing transmission. Gravel can interrupt transmission with larger air gaps and scattering, and loamy soils mix properties that also tend to damp vibrations more than dry sand. So sandy soils transmits noise best.