We extend the bounded-vacuum framework introduced in Ref. [1] by incorporating the intrinsic dynamical properties of localized vacuum configurations and deriving a unified effective field equation for the vacuum potential Φ(x,t). In this approach, matter is identified as a localized vacuum loading corresponding to a deficit of the vacuum potential. We show that stable vacuum loading configurations have their own intrinsic degrees of freedom associated with vibrations of definite frequency ω_0; small deviations from the equilibrium satisfy the Klein—Gordon-type equation, so that the dispersion relation gives the known energy-momentum dependence E^2=p^2 c^2+m^2 c^4, where mass originates due to the condition ℏω_0=mc^2. The field equation under discussion includes not only the wave propagation, but the effect of gravity and the restoring force which represents a sort of the vacuum capacity limitation; in such a way we get the unified treatment of the problem of both massive and massless particles. Within the nonrelativistic limit, the theory turns out to be nothing else but the Schrödinger equation with the effective potential associated with fluctuations of the vacuum potential.