Bob, I look at the relationship between amp type and speakers this way. I suspect we are probably saying the same thing, but just a little differently.
For example, asssume a speaker was voiced/designed to be driven by an amp having a very low output impedance, typically a SS amp. Also assume that the speaker has a ruler flat frequency response if driven by a SS amp, even though its impedance varies as a functiomn of FR. As a result, regardless of whether or how much the speaker's impedance changes as a function of frequency response, and correlatively the amount of current/power the amp produces, the speaker should hopefully have a flat frequency response as a function of frequency -- as posited.
By contrast, if that same speaker is driven by an amp having a "high'ish" output impedance, typically a tube amp like an Atmasphere OTL, then the interaction of the speaker's impedance which varies as a function of FR and the amp's high'ish output impedance will produce sonic colorations because the amp will deliver current/power in amounts that differ from what a low impedance SS amp would deliver.
I'll leave the theory to the EEs, but I believe it relates to Ohm's Law.
Where amp and speaker matching get interesting is in the in-between world. For example, my ARC Ref 150 tube amp has a rated output impedance off the 8 ohm tap at low frequencies of something between .6 ohms and 1 ohm. As a result, there is some sonic coloration if the amp drives speakers designed to be driven by a SS amp, like my Paradigm Signature 8, but the coloration is quite tolerable. Perhaps a tad tipped to the bright side because impedance peaks at 20 ohms at the 2.2K Hz x-over point.
I suppose in a perfect world, a speaker with a ruler flat 8 ohm impedance curve and zero phase angle over its entire FR spectrum would be able to do double duty as both SS amp and tube amp friendly.
Cheers,
BIF
