The spatiotemporal evolution of the naturally occurring dust acoustic wave mode is experimentally investigated in a weakly coupled dc glow discharge dusty plasma system over a range of neutral gas pressures through the application of a time-resolved Hilbert Transform. Frequency clusters are observed over a range of neutral gas pressures, though their spatial distribution varies with neutral gas pressure. It is also observed that the wave frequency is observed to drop by ∼ 10 Hz across these frequency clusters independent of the experimental parameters.