In 1960 Sennheiser presented the MD421 to the world and it put the Sennheiser name on the map. Sennheiser created their first headphone -the HD414 after 4 years. Sennheiser produced it for 15 years and sold over 10 million units which is extremely impressive. They patented the open ear design for 25 years. Sennheiser employs […]