That's not exactly my understanding of the problem on the amplifier side, else a result like this wouldn't make much sense to me:
Sorry, not sure what you referred to. Your diagram is not clear and I wouldn't want to guess.
As you'll note, voltage output remains consistent across phase angles, even down to 1 ohm, where current limiting is obviously an issue. In the prior graph, voltage output sagged according to phase angle at the same ohm steps.
I have listed the power formula on this forum many times in the last several years, most recently in my post#57; and here it is again:
Power (in watts)= Voltage (in volts) X Current (in amps) X cos (ø)
where ø is the phase angle between the current and voltage phasors (AKA vector), and cos (ø) is AKA power factor.
One could include a distortion factor as well but for all intents and purposes, P=VI cosø is close enough.
So you can understand if ø is 60 degree, since cosø = 0.5, power in watts would be halved for the same voltage and impedance (hence current), or if you want to maintain the same watts, the current has to increase by a factor of 2 (what I said in my previous post). Also, note that impedance is not in the equation, but it's effect is represented in the formula none the less since V=IZ (Z is impedance, that includes resistance R, inductive reactance 2лfL and capacitive reactance 1/2лfC).
My understanding of the aforementioned equation (which could be full of BS, as I'm no electrical engineer)
I am, and the power formula is well know enough you don't need to be an EE to know anyway, very googleable as well as you know.
is that for a specified voltage output, power to the speaker will be reduced versus a load with no reactance, so you'll need to drive to a higher voltage and consequently current level to reach the same apparent power output. I'm open to ridicule if I'm full of crap.
Correct, more or less what I said just in different words.
I understand, and would generally agree. Just trying to point out where some failures to communicate/discrepancies between these calcs and real world listening may come into play.
Agree, but not in the case where people claim even at 1 watt there are differences between amps. Well as you know I do question that kind of claims (not saying they are always false), but unless the amps in question are not well designed/entry level ones etc., defective, or there are something else at play, including Placebo, they shouldn't have trouble outputting 1W clean and relatively at very low distortion. At higher SPL and power requirements, yes some speakers, though relatively rare, could be problematic and I have never disputed such claims.