We propose to combine MDI mode parameter and image data with theoretical treatments of the interaction between p-modes and inhomogeneities in the solar envelope (fibril magnetic fields, convective plumes) in an attempt to understand the lifetimes of solar acoustic waves. Lifetimes will be estimated from mode linewidths where feasible; for shorter-lived modes we will use time-distance and related local wave analyses to obtain these estimates. We will first attempt to determine whether the lifetime data are consistent with a depth-dependent energy loss function. We will also compare the observed trends in lifetime vs. $l$ and $\nu$ are consistent with theoretical models of the interaction between p-modes and fibril magnetic fields, and/or turbulent convection.