Headphone School: The World's First Koss SP/3 Stereophone That Started It All

Headphone School: The World's First Koss SP/3 Stereophone That Started It All

In 1958, John C. Koss invented personal listening with the world’s first SP/3 Stereophone. Koss sought to replicate the excitement of a live musical performance and 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.

SP/3 Stereophone

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. The revolutionary sound of the Koss SP/3 Stereophone became the hit of the show and forever changed the way we all listen to music.

ESP/6 & ESP/7

Throughout the years Koss has invented some of the world's most revolutionary headphones, and in 1968 Koss would continue that innovation when they introduced the world’s first self-energizing electrostatic headphone - the Koss ESP/6 followed by the ESP/7 in 1969.


In 1970, Koss set the standard for full-size professional headphones with the iconic Pro/4AA. At the time of their introduction, the Pro/4AA were regarded as the first dynamic headphones to deliver true full frequency and high fidelity performance with impressive noise-isolating capabilities.


In 1974, Koss released the HV/1A, the first dynamic headphone capable of reproducing all 10 audible octaves. The HV/1A paved a new course in personal listening. The unmatched sound, and modern dynamic speaker elements found in Koss Headphones today are a direct evolution from the legendary HV/1A.

Porta Pro®

In 1984, the acclaimed Koss Porta Pro® set performance and comfort standards for portable personal listening - worldwide. Designed for those with a refined ear for music, the Porta Pro continues to be one of the most popular headphones around the world. 60+ years after the introduction of the world's first SP/3 Koss continues to innovate personal listening with headphones like the Pro4S Studio Headphones, KPH30i, A/550 and ESP/950 - continuing the dream of founder John C. Koss and bringing people closer to the music they love.
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