"Onkenhornreflex" design from Germany?

I've been researching about Onken cabinet parameters because I am intrigued by possibly using that type enclosure for something I want to design and build--
--but it seems like the characteristics of a majority of modern speaker drivers cause the Onken calculators to specify silly-long vents.

I ran across some seemingly intriguing discussions and builds on German diy audio forums in which they've supposedly come up with a design that they're referring to as "Onkenhornreflex" and which supposedly shortens the required length of the vents.

One set of conversations:
(original German)(seems to be by (maybe) an originator of this combination of design characteristics):
Klang+Ton-Forum • Thema anzeigen - Bauanleitung Onkenhornreflex CT230 bzw. Aurum

after being fed through Google Translate:
Google Translate

A different thread with some greater detail of the design itself and of the construction techniques:

Nachbau von Kalles Aurum Hornreflex
Nachbau von Kalles Aurum Hornreflex

[and a related "construction diary"]:
Kalles Aurum Hornreflex [Bautagebuch], Projekte der Nutzer / Nachbauten - HIFI-FORUM
{google translated):

The idea seems to have emerged out of discussions that began here, although I am not connecting the dots to understand how it got refined into specific formulas or measurements to apply:

(google translate)

Are these fellows "onto something" or is this just some sort of lucky accident that they came up with something that sounded good?