Wave Velocity vs Wave Frequency. Wave velocity and wave frequency are two very important properties of a wave. The wave velocity describes how fast the energy is propagating. The wave frequency describes how fast the wave is oscillating. Both of these properties are very important in defining and describing the wave. Wave velocity is a property of the medium for a certain type of wave. The wave frequency is a property determined by the frequency of the source. • Wave frequency stays constant regardless of the medium the wave is travelling on. Wave velocity changes with the medium.