In Part II, the mixing of the sources was specified to be instantaneous and the Regression/mixing coefficients were specified to be constant over time. In this Chapter, the sources are allowed to be delayed through the Regression/mixing coefficients and the Regression/mixing coefficients are allowed to change over time. Delayed sources and nonconstant or dynamic mixing coefficients take into account the facts that speakers at a cocktail party are a physical distance from the microphones, thus the sound from them taking time to travel to the various microphones at different distances, and that the speakers at the party may be moving around.