One embodiment provides a method comprising determining an energy stored in a port of a vented box loudspeaker based on a physical model of the vented box loudspeaker, determining a time-varying attenuation to apply to a source signal for reproduction via the vented box loudspeaker based on the energy stored in the port, and controlling the energy stored in the port in real-time by attenuating the source signal based on the time-varying attenuation. A velocity of air in the port during the reproduction of the source signal is limited based on the controlling.