The Sennheiser HD414 changed the headphone game in 1968.
They were exciting, not only for their ‘Open-Aire’ design (a first) but also for their bright yellow foam ear pads. Remember, In those days audiophiles were listening to big, bulky and heavy closed-back models. The HD414s looked, felt and sounded like nothing else and forecast the future direction of headphone design and sound.
Although they were designed as a consumer model, the HD414 were very popular with audio professionals. More than 10 million HD414s where sold, making it the best-selling quality headphone of all time.
Sennheiser eventually licensed Open-Aire technology to Sony for its first-generation Walkman headphones.