1958

SP/3

The World's First Koss Stereophone

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. The original SP/3 stereophone allowed listeners to experience sound as they had never before, bringing them closer to the music they love.

1968

ESP/6

In 1968, Koss released the ESP/6, the world’s first self-energizing electrostatic headphone. To achieve its unprecedented sound profile, the ESP/6 employed the principle of a currentless, or electrostatic charge. The charge was applied to push-pull condenser plates, and caused movement of an ultra lightweight conductive diaphragm.

1970

Pro/4AA

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.

1974

HV/1A

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.

1976

Pro/4AAA

In 1976, Koss introduced the Pro/4AAA. Building off of the Pro/4AA’s iconic sound, the Pro/4AAA incorporated a number of new design features. The most notable of these features was the headphone’s Direct Contour Pneumalite ear cushions. The shape of the cushions mirrored an ear’s natural “D” shape. This advancement in design informed the very pronounced “D” Profile found in many Koss headphones today.

1984

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.

1989

JCK/300 Kordless Stereophone System

In 1989, the Koss JCK/300 cordless headphone set the standard for infrared wireless headphones. By developing a new transmitter that delivered four times more power than conventional infrared headphone systems, Koss cut the cord and changed personal listening forever.

1990

ESP950

In 1990, Koss introduced the revolutionary ESP/950 electrostatic headphone. The ESP/950’s breakthrough design incorporated electrostatic transducers with ideal mechanical damping. The unit’s distortionless sound is attributed largely to its ultra-thin (1.5 micron) diaphragms. Each diaphragm moves uniformly thanks to an electron deposited proprietary semi-conductive coating.

2014

BT540i

In 2014, Koss once again cut the cord with the BT540i wireless Bluetooth® headphone. A technological powerhouse, the BT540i incorporated a state-of-the-art Bluetooth chip, NFC® one-touch pairing, and near-lossless sound with aptX® codec.

2014

Pro4s

Carrying on the legacy of the Pro/4 line, 2014’s Pro4S studio headphone was specifically crafted for audio professionals. Featuring the all-new SLX40 element, and iconic “D” Profile shape, the Pro4S delivers remarkably accurate sound.