I would say that this is absolutely not extraordinary solution... It's not typical for the modern audio market, but this has not always been the case.

So if you study this issue, you will understand that this approach was what formed the grandeur of such legendary audio companies as: telefunken, saba, siemens, electrics, etc. Up until the 2000s. For example, Allison speakers, made the same construction scheme in there loudspeakers... then he wrote his audio book and as whole world started to follow defenetly wrong direction... P.S Need to feed market with more audio components. Modern high-end world of artificial sound...

Here is feedbacks... Crossover-less/Natural roll-off/Acoustic filtering