@mahgister
Van Maanen said explictly that he use real MUSIC signals not artificial tones or continuous sine wave to test his design and measure their behaviour under stress ....And he described in his articles how he designed his own amplifiers... He is not in the job of comparing amplifiers as you did with some set of linear measures...
Oh yes he is. See his other paper here: https://www.temporalcoherence.nl/cms/images/docs/DynamicResponseAmplifiers.pdf
Title: "Tone burst response of amplifiers to determine some properties of their dynamic behaviour"
Then he says this:
"To that end, two high-quality amplifiers with clear differences in their perceived sound, have been tested with tone-bursts. In this report, only the results at 30 Hz will be reported and discussed, as at these low frequencies the issues show more clearly."
See? Not only does he use classic test tones, but says it "clearly" shows the difference between the two amplifiers. Here is one of his graphs for the first amplifier:

Please explain to me why it is OK for him to run such tests when you claim any such test is based on "fourier theory" and therefore invalid. I remind you that this is your expert witness.