The main guy at Neumann besides Georg Neumann was Erich Kühnast. But no one ever left and there was never a split. There were two factories/companies: one in Berlin and one in the town of Gefell.
There's some history here.
http://www.gefell-mics.com/gefell_history_1.htm
Sennheiser owns the Neumann brand today. The Neumann mic you know today has little to do with original Neumann company.
The real Neumann mics are made by Microtech Gefell - the official name being 'Georg Neumann KG'. Gefell is owned by the Neumann family.
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Additional Information:
The History of Gefell
Georg Neumann started his illustrious company in 1928. During the Second World War manufacturing microphones in Berlin was no longer possible, so in 1943 Georg Neumann and chief engineer Mr. Kühnast moved the company to the village of Gefell, a safe, quiet location in an area of Germany that would eventually become part of the eastern block.
After the war, Georg Neumann was invited by the French government to set up a laboratory in Paris. There he invented the gas-tight nickel-cadmium accumulator. Mr Kühnast continued to work in Gefell while some members of the staff returned to their home city of Berlin and started a branch company, which acted as repair centre for Neumann products in West Berlin. These are the roots of the second Neumann Company, which was founded in 1948.
Both Neumann Berlin and Neumann Gefell worked closely together until 1961 when the Berlin wall was erected. During that period, key engineering staff worked at both facilities, which were also frequented by Mr. Neumann on a regular basis untill he passed on 1976.
The original company, Neumann Gefell, continued its path developing microphone technology including a tremendous range of test and measurement microphones that today rival any in the world. This of course lead to the development of metal diaphragm microphones for precision recording, and during the next 40 years Gefell accelerated the development of tube technology which as everyone knows, continued in eastern Europe while the west developed transistors.
In 1989, with the collapse of the Eastern Block, Georg Neumann`s family saw the opportunity to get its property back in Gefell. By this time, the Berlin factory was in trouble. The company had expanded into other areas, which included disc cutting (vinyl) and custom console manufacturing, neither of which were sustainable businesses. In fact the Berliner Bank shut down the Georg Neumann GmbH Berlin factory, and in 1990, arranged to sell the company to Sennheiser who immediately moved what was left to the Sennheiser assembly line.
In 1993 'Georg Neumann & Company Gefell, GmbH' was given back to its original owners, the Neumann family. Ownership of the company today is retained by the directors of Microtech Gefell with the official name being 'Georg Neumann KG' (no relation to the Sennheiser Corporation's 'Neumann' brand name, which they purchased in 1991). The Gefell condenser microphones of today are still manufactured using the original techniques and exclusive processes developed by Georg Neumann. This includes the famous M7 capsule, which is to this day at the heart of many Gefell microphones.
Over the past five years, the Neumann-Gefell team quietly started to redefine microphone technology and adapt it to the growing demands of digital recording. Microtech Gefell has since set a new bar by lowering self-noise and increasing sound pressure handling capability beyond all others. Other innovations include the worlds only phantom powered tube microphone, a ‘line array’ microphone for precise signal steering, and some of the smallest measurement microphones in the world.
Classical recording is the ultimate engineering challenge: a full orchestra can generate a sound field that can be 100 feet wide and 40 feet deep and capturing the tremendous dynamics is no small task. The world’s most demanding customer, the German Broadcast Corporation, recently selected Microtech Gefell as ‘their new standard’.
Just as they were 75 years ago, Microtech Gefell microphones are still hand built, individually tested and measured to ensure a quality level that is unsurpassed. The passion and care is evident from the moment you open a jewel box and plug in.
