A case can be made that any speaker with great swings in impedance is not a well designed speaker as a whole. Yes there are solid state amps that will drive a 2 ohm load, but why limit the user to solid state and why design in this fashion? Makes little sense to make a 95 db efficient speaker that goes down to 2 ohms. Attract the tube crowd with high efficiency and then alienate them with poor impedance performance. Check out the impedance swings in much of the Wilson line. Funny thing about Wilson is that the best I have heard them sound was when being driven by a low powered tube amp.