Phonogen
Company profile
Norbert Schäfer, born in 1942, had already started building loudspeaker boxes during his physics studies at the University of Stuttgart.
From about 1968 on, the student worked on folded horn constructions, which he initially realized in wood, which, however, tended to resonate in different ways at different points of the horn. In addition, the type of processing, with smooth surfaces and sharp angles, ensured that standing waves could form again and again, leading to sound distortions.
The solution seemed to be concrete. On the one hand its strength should prevent the resonance of the housing, on the other hand it could be cast. This form of processing made it possible to do without flat surfaces and the aforementioned sharp angles as far as possible.
Since the professional production of mould and casting by a specialist company was not affordable for a student, Norbert Schäfer developed the mould and the process himself during two years of tests, in addition to his studies.
In 1975 the first bass horn made of concrete and plastic, named "Phonogen", could be presented by the Expophon KG in Beuron-Hausen / Ts., which was founded especially for this purpose. The construction and manufacturing was done by Norbert Schäfer, the outer design of the box was realized by the designer Holger Scheel.
Apart from its manufacturing technique, another special feature of this exponential horn was its drive: the diaphragm was divided into two sections by means of a glued-on rubber lip, one of which was to reproduce the frequency range between 18 and 250 Hz, and the other that between 250 and 600 Hz.
To create a complete full-range speaker, the horn was supplemented by a conventional midrange driver and a rotatably mounted electrostat.
In 1978 an active version Phonogen 1a was added to the Phonogen I speakers now offered by Phonogen Norbert Schäfer KG in Beuron.
In 1979, on the initiative of the trade magazine AUDIO, a cooperation with Mr. Friedrich Müller and Mr. Wolfgang Backes took place, resulting in the Reference.
For the 1980 model year, Phonogen Schäfer KG, now based in Epfendorf-Talhausen, presented two new loudspeakers, the Phonogen Live and Concert, which followed a completely different design concept than the bass horns with which Phonogen had become known. At the same time Norbert Schäfer, under Günther Seitz, was engaged in the development of Canton.
From about 1982 onwards Norbert Schäfer started with large diaphragm experiments and thus developed a third design principle for clean bass reproduction, which culminated in the development of the "Trans" series in the second half of the 1980s.
With the help of an investor, the now Phonogen Lautsprechersysteme GmbH (Kirchhalde 19, Großbettlingen) could realize the production of the Phonogen Transfer. AUDIO reported, on the occasion of a test report (12/87), that a larger model 'Transline' had already been announced.
Despite the positive response, Dr. Hans-Joachim Rebmann, owner of Phonogen GmbH, sold his shares in the company to the Munich-based ATL Elektro Akustik GmbH, which also hired Norbert Schäfer as a freelance developer. In the summer of 1989, a second generation of the Transfer appeared there, and also the smaller Translife and the larger Transart; shortly thereafter, a top-of-the-line Transmaster was added.
A settlement in 1994 ended the history of ATL and, by extension, Phonogen.
Parallel to his work for ATL, Norbert Schäfer had launched a new generation of loudspeakers in 1992, with Designakustik Schäfer in Oberkässach, and, together with engineer Joachim Zürn, led the Trans series from 1999, with Translife GmbH in Schöntal, into a third generation.
In the meantime, Norbert Schäfer has gone into un-retirement and is currently (as of October 2013) devoting himself to basic research on wave theory.
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