All audio design is based on Fourier tools
Yours included and Van Maanen too...
But for Van Maanen some other aspects of his design are inspire4d by his hearing theory ideas... Then he used music real test also and very importantly..
I thank you for your informative set of measures ffrom tghe beginning... Why ? because this useful...
But i disagree wi5th you vabout the importance of hearing theory and listening test...I disagree with the idea that we can predict more than the behaviour of the electronic compobnents but also their sound qualities... Sound qualities is a set...In this set each sonic character production cannot be predicted as human hearings will perceive it and judged it...
In a word Fourier is reliaqble for circuit design not for predicting all aspects og hearin experience..