I thinking about buying a 950 and a 755 or used 750 and I was wondering something. I have Onix Rockets right now which are 6 ohms except for the center which is 4. I noticed the power ratings in the specs for 8 & 4 ohms. Is the 6 ohm rating considered to be approx. in the middle of these 2 ratings or is it something else.

Thanks

That rating is just a nominal indicator. Actual impedance varies with the frequency being reproduced by the speaker. Regardless the 755 or 750 can easily handle it as would most any decent amp.

Just guess about halfway. It's close enough with amps that don't scale perfectly with the lower ohm ratings. My M200 amps work just fine on my 6 ohm speakers.

As do my Dynaudios at 4 Ohms average, occasionally even less, depending on frequency and output. The M200s are more than enough.