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

shadorne    Horns have lower distortion than conventional drivers faster transient response than conventional drivers,are easier for amplifiers to drive can produce higher SPL than conventional drivers also exhibit greater dynamic range. and radiation pattern control. Consider much of the music that audiophiles collect was mastered on Altec, TAD, RCA and other horn systems. And many modern studios are still using horn monitors.

Your TAD drivers all based on early 1920s designs,the horn of the CAR is just a evolution of a 1940s design. OTL amplifier is from the 1950s sure you improved but you didn't create invent.

OTLs: yes I invented my circuit myself. I didn't know about other OTLs at the time. I got two patents- more than anyone else in the field. More on the way.

While the drivers might be loosely based on the prior art, the fact is nothing like them existed or could have existed as early as the dates above. The simple fact is that computer technology has made speakers better- including horn designs.

Horns are simply not the best in terms of accuracy but they do deliver exceptional SPL for little power - great for live music sound reinforcement.

Actually a good horn can be quite accurate- if you think about it, the driver does not have to have a lot of excursion to do its job. If its properly designed, it can be lower distortion as a result. Since the electronics don't have to work as hard to drive the speaker, its also possible for them to be lower distortion too.

Speaker evolution these last rather many decades roughly seems to have been more about refining a concept born by Edgar M. Villchur when he brought forth the AR-1's in the 50's. Few would or should really contest the perhaps most notable feature here being the catering to a domestic demand (rather than the search for and proclamation of a more real sound), or certainly seeing a product's more widespread use through the limitation of size (made possible with the advent of the more powerful transistor amps to counter another limitation: sensitivity). Within this concept I can see some progress through the years (followed not least by an uptick in price), but in the bigger scheme of things the older, much larger and much more sensitive (horn-)speakers, though limited in the frequency extremes, to my ears are still substantially in the lead (particularly combined with low-wattage, single-ended valve amps) when it comes to an effortless, dynamic and encompassing live/emotional imprinting. From this perspective it could be argued that over a longer timeline speaker evolution has really seen a decline, in some vital aspects at least, in not re-accepting the need for sheer size and high sensitivity of speakers. From my chair we'd need to re-visit these older horn designs more frequently, and build/design further on from them to truly make progress. 

Atmasphere -Look at 1920s WE 555- 1930s 596A compression driver your saying TADs design isn't based on these early compression drivers?  Whats so different besides materials used?                                   I never knew you invented OTL I assumed it was created in 1954 by Mr Cecil Hall for EV. 

Phusis,{From my chair we'd need to re-visit these older horn designs more frequently, and build/design further on from them to truly make progress}  Much of modern design is about making things smaller maybe with loudspeakers if ultimate performance is end goal we might have taken the small approach a bit to far.