Erik Rorbaek Madsen (Erik Rørbæk Madsen), a native of Denmark, was born in 1915 and became designer of the tonearm and the MMC cartridge principle with Bang & Olufsen. He became well-known for the design of his pickup cartridges in the 1950s.
Introduced in 1958 Bang & Olufsen’s SP1 cartridge included a delicately-manufactured integrated stylus with which made contact with a disc in order to read it. Technology had changed rapidly in the years preceding the introduction of the the SP1 with pickups retaining their ‘heavy-handed’ appearance in both looks and in use with styli previously being fitted with metal needles ‘cutting’ their way through prized Shellac records. However, with the introduction of stereophonic micro-grooved discs in the late 1950s - and following Madsen’s visit to the US in 1956 - feather-light micro-magnetic cartridges with their own interchangeable sapphire styli became the norm due to his suggestion - and subsequent acceptance of an international standard of 15° for the vertical cutting angle at the recording of gramophone records. Previously, this cutting angle varied greatly, which led to all pick-ups could not play all records with equal success. Today the 15° cutting angle is an international standard used by all manufacturers - and was found throughout Bang & Olufsen’s diamond styli range of pick-up cartridges.