The interaction of an acoustic pulse with the experimentally determined mean flowfield of a spreading jet has been simulated numerically. The simulation is obtained by solving the Euler equations linearized about the spreading jet. The model shows a small, sustained oscillation long after the original pulse has passed. This remnant is seen as a continual shedding of vortices from the nozzle lip, together with the generation of acoustic ripples. The jet is also shown to act as an amplifier of sound. This amplification is traced to the stability characteristics of the jet. It is shown that some of the observed differences in the spectra of heated and unheated jets can be attributed to differences in the stability characteristics of the jets.