I am not going to argue with you, it is a waste of time. By the way the 10:1 rule came from the era of tube amps. The impedance interactions are real and documented. In fact, Stereophile has been doing measuements into dummy speaker loads for years. You can go back and look at their data. Here is a link to an article printed by them in 1994 which sums up most of what I am talking about as far as speakers/amps. http://www.stereophile.com/reference/810/

If you want to hear what a tube amp sounds like put a 1/2 ohm resistor in series with your speakers. Or to get really close calculate out what you need to get the DF to tube amp levels, something belwo 20, in the case of some a DF of 4 such as Cary. By the way, modern speakers are using more and more drivers with wild impedance swings. You can go to Seas or Tymphany's website and see the impedance plots of the drivers. While some manufactuers use zoebel's to flatten the impedance, 98% do not. I do agree though that active xover's generally do not have wild impedance swings, as they generally use an impedance flattening circuit.

My ic's are 1 meter long and not garden variety, they are not esoteric either. If I recall corectly their capicatance ranges from 28 pico farads to around 100 pico farads depending on which ones. The ones I use most commonly are the 28 pico farad to the CDP(this does not change, as my CDp is sensitive to capacitance on cables) and the amp to preamp use a pair of 50 pico farad cables.

We can go on disagreeing forever, I have been through this too many times. I have done the testing myself and have had it proven over and over to others through testing and results. I will just agree to disagree with you.

Tim