The age of speakers doesn't hold much interest to me unless where it's followed by a shift in design - at least that to me is what truly signifies a "vintage" speaker, when they eschew in central areas what is typically seen with contemporary speakers and for the latest decades now. If age alone was the main factor defining vintage speakers - that is, counting no more than 30-40 years - I'd find their use mostly trivial and lacking compared to their newer siblings in light of the (lack of) development found in this period of time; age would simply begin to slowly work against them, with nothing really to "counter-balance" this decline inherent to the design. Going back 40 or more years, to me, is where vintage begins to truly establish itself via different, and physically larger designs - mostly horns. Really interesting is where these vintage designs are sought refined through re-builds with better materials and construction (cabinetry), better cross-overs, and the equivalent in or evolutionary advanced (pro-)drivers. Vintage designs by that nature hold advantages through sheer size, principle (i.e.: horns), sensitivity, and the type of drivers used. Where these are sought refined (or even replicated/used as is) I find them potentially much more interesting and authentic sounding than contemporary designs of the typical "acoustic suspension"/direct radiating design philosophy brought forth by Edgar Villchur in the early 50's. Hearing some of these vintage speakers is oftentimes a revelation, and makes me wonder the direction "hifi" has taken in the latest decades - for something that is essentially better? No, to the contrary.
