Loudspeakers have we really made that much progress since the 1930s?

With regards to the Shearer, while solving a lot of problems of the prior art in its day, it also had problems of its own. Many of these were addressed in the Altec VOTT designs. And they were pretty well universally acknowledged as improvements.

I ran VOTTs for a number of years. Then a friend lent me a set of FMI 80s. We set them up in the same place as occupied by the VOTTs and the improvement in imaging, nuance and bass impact was immediately apparent. Mind you, the FMI80 was a simple 2-way bookshelf speaker with an 8" woofer. The one thing that they could not do better was high volume, which one would expect.

These days the speakers I play have far more resolution than those FMI80s, far more bandwidth too, yet the efficiency is up at 98 db, allowing for that sense of power and air that you only get when the amp does not have to work for a living. So I see that as a huge improvement over the VOTTs, which were allegedly (as seen on the JBL/Altec site linked in the opening post) better than the Shearers. Now, if logic is still something you can use, that must mean that my speakers sound better in nearly every way than the Shearers. My speakers BTW are the Classic Audio Loudspeaker project T-3.2, equipped with the field coil midrange drivers. They are not the best that Classic makes, but they do fit in my room which is a plus (the T-1s do not).

I get the romantic experience that is part of the vintage scene. That romance is not just in audio; I love to ride a vintage motorbike or bicycle as well. Such things often have a certain charm. But that charm is only available through experience, regardless of the measurements.

Seems like a lot of discussion about drivers and slopes. How about cabinets, materials and resonances. 

I tend to agree with those who are saying that things, overall, have tended to improve with time, better highs, better lows, for sure. But even so, I gotta say that the humble, successfully-well-thought-out, untreated-paper cone midrange is still...pretty damn stout, actually. A righteous thing still IMHO, even today...cliche, maybe, but true!

Wrong! Clearly you don’t know anything about Violins and there is no comparison that makes any sense between an old Violin and an old speaker. An ideal speaker should have no voice of its own.

The problem of this statement is comparing real speakers VS ideal speakers. Ideal speakers is better, no question, but as far as I understand, the ideal speaker nor violin never existed, and it will not.

I started thinking that the ideal electronic to acoustic conversion (vice-versa) is not determined by measurable specification. If so, measurement microphone is the only microphone needed in the professional recording process, but I have never heard someone records the musical instrument with a measurement microphone.