One of the most storied companies in headphones, Koss was founded in the US 1958. John C. Koss teamed up with engineer Martin Lange, Jr. to develop a portable stereo phonograph player with side-wing speakers. The pair demonstrated their new stereo record player at a Wisconsin audio show.

One of the product's unique features was a privacy switch, which allowed listeners to hear music by plugging in the world's first SP/3 stereophone. The stereophones were intended to be an accessory to demonstrate the high-fidelity stereo sound that the portable phonograph player delivered.

Decades later, and Koss is still inventing, with legendary designs such as the Koss Porta Pro being updated for the modern age of portable audio.