Hey shadyj, thanks for the reply. The MK442T speakers you linked are 4ohm as well so I'd have the same problem. When you say listening at loud levels, what is considered loud to an audiophile? I did plan on using this system to listen to music as well and was going to take the advice of the author and upgrade to 5 MK442's to use as LCR and rears. My idea of loud is in the 85 to 95 decibel range. I don't think I'd ever listen to music that loud and for long these days. I think for me, the loudest I'd ever play music would be around 75db and the loudest I'd ever play home theater stuff would be in the 60 to 65db range. Would those levels, give or take a couple decibels, be harmful to the AVR in this set-up?
I wouldn't pay too close attention to base specs such as '4-ohm' or '8-ohm' and instead look at measured impedance charts, which tell the real story. What you want to look for is where the impedance curve dips the lowest and how steep the phase curve is at that point. That is far more relevant than some nominal ohm rating. Let's take a look at the MK442T impedance chart:
Here we see it does dip down to 5-ohms from 200 Hz to 300 Hz, which is actually a very heavily used band, but the phase angle isn't too severe. A budget AVR could run this speaker, but if you ran it loud for a long time, than maybe the low impedance of this range might catch up to the AVR and send it into auto-shutdown.
Now let's take a look at the MK442 MTM speakers:
They do have a similar dip in the same range, similar phase angle, but they also dip down to 4 ohms at 4 kHz with a sharp phase angle. It's a harder load, but again, if you don't blast this speaker, it will probably be fine on your AVR. Not the most benign load and not the worst, but it depends on how you use the speakers.
My guess is that you won't be pushing the system hard enough to send it into shutdown. Can you tell me the size of the room that you are listening in? Also, what will be the distance from the speakers to the listening position? Telling us dB that you listen at isn't all that informative without that other information.
