Interesting general idea lifting these products out of the haze of history and tell what they actually whereI'd love to compare the (already measured) Advents to Dynaco A25s. I'd like to match the myths to reality, not in absolute terms (old crap is old crap), but on a comparrative basis.
There was(is?) not always complete science about how to make stuff some used the best knowledge of their time some just whinged it based on myths ( just like now ).
There is always something interesting in the turns things takes before settling into a formula.
Some older speakers could have decent drivers but bewildering acoustical property’s or the other way we’ll controlled directivity like large horns but weird drivers and horn shapes and distortion issues otherwise .
Some old amps shoved interesting and innovative design but had other shortcomings that made them differ more than modern products?