Nope. It is you that is not understanding the topic or that measurement. First, show the link to the reviews on stereophile and not just the graphs. Here is the link:
https://www.stereophile.com/content/primaluna-dialogue-seven-power-amplifier-measurements
Right there, JA explains what is going on which is what I explained:
"In
8 ohm impedance feeding an 8 ohm load transfers more power to the load than would a greater or smaller impedance. However, there is a price to be paid: because loudspeaker impedances vary considerably with frequency, high output impedances result in significant modification of the amplifier's frequency response, due to the
Ohm's Law interaction between the amplifier and loudspeaker impedances. This is illustrated by the gray trace in fig.1, which shows the DiaLogue Seven's frequency response from the 4 ohm tap in ultralinear mode into
Stereophile's standard
simulated loudspeaker."
As I already explained, the response changes due to high impedance of the amplifier, in this case 8 ohm. This clearly shows up in response differences of 4 vs 8 ohm. Ohm's law works there and as JA says, it works exactly the same in a varying impedance load. At any point in that varying load, you can use the simple Ohm's law to compute the impact. No new insight is gained other than application of Ohm's law to resistive vs reactive load. This is why i said the impact on your actual speaker will be different. Best to avoid these amps with high impedance. But if you can't avoid it, then use acoustic measurements to deal with it. Nothing is gained by looking at at that simulated line. The only insight was 8 ohm impedance of the amplifier. Period.
