All speakers have a resonant frequency and therefore can be excited into resonance at that frequency. A pulse sent to them will tend to cause overring, and the alignment will determine the amount of damping. This is what determines the amount of a "ringing" artifact is produced - Not whether it is sealed or ported, but rather the Q of the particular alignment.

The speaker diaphragm and suspension is a spring/mass system which is mechanically reactive. There's no way around it. A sealed cabinet will offer damping - like that of a shock absorber - but it is helpless to remove the "spring" action in this system from the diaphragm mass and suspension. So a sealed cabinet can assist the motor by damping it, but it cannot remove the reactive nature of the mass/spring action of the motor.

You will see a similar sort of "ringing" at resonance in a sealed cabinet as you will in a bass reflex cabinet. The more damped a system is, the less it will ring. But this is determined by alignment, and not by whether a cabinet is ported or not. As we examine this a little further, we actually find that a sealed box is incapable of providing as much damping as a optimally tuned bass reflex box, at least in the resonance region between fb and fh.