= Acoustic attenuation
<Acoustic attenuation> is a reduction of a propagating <sound> signal beyond that attributed to the specified geometric spreading. <Absorption> converts acoustic <energy> to other forms, while <scattering> redirects it away from the receiving path. The inferred attenuation therefore depends on what the detector collects and how the spreading reference is defined.
For a plane wave with pressure amplitude $p(x)=p(0)e^{-\alpha x}$, the corresponding <sound intensity> decays as $I(x)=I(0)e^{-2\alpha x}$ in a fixed medium. An attenuation coefficient defined from intensity has twice the numerical value of this amplitude coefficient. Measuring the signal at several separations can estimate the slope, provided the source response, reflections and geometric corrections are controlled.
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