It's not harder to drive, it's more demanding on the amplifier, which will have more current flowing through it, because of the lower impedance. More current equals more heat and more demand on the power supply, which equals more chance of clipping or shut down.

Last edited by ClubNeon; 03/18/11 07:31 PM.
Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris