I'd disagree with you on the point of transducer theory. It's well understood and poorly published. In particular, proprietary models are significantly more rel

I'd disagree with you on the point of transducer theory. It's well understood and poorly published. In particular, proprietary models are significantly more reliable than what is publicly available (both for old school lumped-element and newer finite-element analysis), and the major manufacturers keep those close to their chest. Even the published models by those engineers are glorified approximations of internal research. The limiting factors are in manufacturing, where DIYers and small shops do not have access to the materials and testing equipment of the big players. I think the real elephant in the room is that audiophiles spend a lot of money and don't like being told they're wrong. There's a weird psychology in high end audio (both professional and consumer) - sales are made based on the users' preconceived notions about the product/brand, and you make money by playing into those notions instead of trying to subvert them. PS: based on your username, I think I apprenticed under you a few times.