Visualizations, based on a diffusion equation model, are presented for both steady-state and transient sound energy. For steady-state sound-pressure level distributions, animations created by scanning from the primary room to the secondary room reveal discontinuous transitions of sound energy caused by a location change from the wall area to the aperture area. Animations of time-dependent energy flow directions visualize the energy flows across coupled spaces. This study also reveals a "reversal" characteristic of energy flow directions which seems to be dependent on the size and location of the aperture.