4 ohms vs 2 ohms

Is there a noticable sound quality difference running a 4 ohm sub instead of a 2 ohm one?  That is, if you had two identical subwoofers (with the exception of one being 2 ohms the other being 4 ohms), and you hooked the 4ohm sub up to an amp outputting, say, 500watts at 4 ohms, and then hooked the 2ohm sub to an equivalent amp running 500w at 2ohms would you be likely to hear a noticable difference between the two? (i realize it couldn't truly be an "equivalent" amp because there would have to be some inherent differences between the two, given that one is outputting 500w at 4 ohms, the other at 500w at 2 ohms--but ignore that fact, if possible, for the sake of question). 

Any noticeable difference would be from the 2-ohm speaker placing twice the load on the amplifier with the possible resultant increase in noise and distortion from the amp.  Other than that, no.Support the12volt.com

Most amps will post a high damping factor at 4 ohms as opposed to 2 ohms. Would it make enough of a difference to be detectable with the ear alone? Depends on the equipment and the ear... Personally I try to run at 4 ohms whenever practical.