Quote:
Originally Posted by
EJRothman 
Also they website says that the nominal impedence is 6 ohms and the minimum impredence is 4 ohms. What's the difference here? Can these speakers be run safely with receivers rated for 6 ohms only or should they be run by something rated for 4 ohms?
-Eric
As an Electrical Engineer I will try to shed some light on this for you. There are other places on AVS that have info on this as well.
Speakers have a dynamic impedence (resistence or load ) and the impedence changes depending on the frequency of the signal and the amplitude (volume) and can range anywhere from 2 ohms to 10 or more.
The Nominal impedence is the average impedence the receiver will see or more accurately what the speaker will measure when there is no power being applied.
Minimum impedence is considered the lowest impedence the speaker will show at any frequency provided. Now this isn"t always accurate and speakers will go lower than that at times.
You need not be worried. If you are using an EXTREMELY cheap receiver

you may run into a problem of overheating, but that is about the only problem you will see. Also, most receivers that are ~$350 and up are going to work just fine unless you are really trying to crank the volume up for long periods (ie. college parties).
I have to say that in my experience (lots of college parties

), I have seen many different brands of receivers used and found that Denon receivers out perform all others when it comes to this, without going to highend receivers ($800 and up).
Plus this problem has become less of an issue in recent years as receiver quality has gone up and prices down.

The Alpha series should pose no problem for you if running a "8-ohm rated" receiver.

Regards,
TREVOR