I don't have enough technical knowledge in this field to authoritatively refute the claim. But I will take a stab at interpreting it, which is that the paper is looking for cost effective near field performance, rather than the best performance. There is little doubt that well-made active monitors offer the most cost effective hifi performance. The cost effective market has little overlap with the market for flagship products such as the la90.
In addition, the paper you quoted handpicked parameters such as the "typical listening volume" parameter without justification. I guess the author is lacking the tools that Amir has, or doesn't want to use them for some reason, but I would expect a 3d graph for each amplifier of thd+n vs frequency vs wattage if the author was trying to be thorough in making his point.
Finally, before the author's "cost compensation," significant differences do appear in the measurements.
TLDR: The paper does not "prove" to be that the loosely defined heuristic is a mathematical fact to my mathematically trained eyes.
You asked for the paper, I provided. I am not saying I agree with everything in it but I think it is clear that high distortion amplifiers can be used in really good sounding speakers (Genelec, Neumann, JBL, etc). This of course would imply that amplifier THD is just not that important to sound quality.
Here is a math question for you, what is the rough contribution on system THD of an amplifier with 0.05% THD when combined with a speaker with 0.5% THD? Do you think it is significant?
EDIT: To make my point even clearer, what amplifier do you think Amir uses when testing speakers on the Klippel? Do you think it is SINAD superstar? It is not -> https://www.audiosciencereview.com/...-about-speaker-measurements.11139/post-315631. And yet it is good enough to quantify performance of very high performance speakers.
I don't use their amplifier (it is too low power made for driver testing). The one I am using is one that I have reviewed before (Behringer A500): https://www.audiosciencereview.com/...easurements-of-behringer-a500-amplifier.5070/
Michael
Last edited: