A "Tier 2" engineer I have made contact with at Denon/Marantz said some things that kind of go against a few standards I always thought were gospel (with regard to AVRs and impedance/sensitivity). Primarily:
Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power.
And:
Yeah. This is a common misconception. Regardless of which setting you choose the receiver is going to present the same amount of power, but lower impedance speakers will be able to use more of it. The 8, 6 and 4 Ohm setting is just there to tell the receiver what to expect. It does change how some of the power handled, but I am not clear on exactly what is different. I just know the same amount of power is available either way, but if you do use the recommended setting with lower Ohm rated speakers you are less likely to have the unit over heat and suffer potential damage as a result.
And:
If all of your speakers are 8 Ohms, then you can safely ignore this setting. If even one of them is 6 or 4, then you should be using it.
I was under the impression -- and someone please correct me if I'm wrong -- that low impedance makes a speaker MORE DIFFICULT to drive, not easier, as he suggested. With regard to the ohm settings, he provided that response after I asked about always keeping an amp/AVR on 8 ohms regardless of what's connected -- he's claiming that it's a misconception that AVRs should always be kept at 8 ohms (if selectable) so they always put out the most power. I was always under the impression that setting should ALWAYS be 8 ohms, but he's saying if ONE of my speakers are 6 or 4 (which none are, as far as I am aware), that ohm selector should definitely be taken OFF 8...
Any thoughts on this?
