Massdrop x Koss ESP/95X Electrostatic System

A revival of the standard-setting ESP/950 released by Koss in 1990, these headphones bring electrostatic quality into a whole new price bracket. Initially designed for live recording, the ESP/950 came with a large carrying case and a battery pack to power the required energizer: a special amplifier for electrostatic drivers. Made for the modern audiophile’s listening purposes, this version skips the case and battery pack to save on weight, space, and cost. The color has been updated to Massdrop’s exclusive midnight blue and the pleather ear pads swapped for thicker, more comfortable foam wrapped in velour. The rest stays true to the original: same clean bass and unmatched sound quality; same pivoting cups and adjustable, detachable headband; and same energizer, now with new graphics and colorway—all backed by the same lifetime warranty.

Invented in the 1800s and still widely used today, conventional moving-coil drivers feature a coil of wire inside a magnet glued to a stiff cone. Current passes through the coil and electromagnetism creates force that vibrates the coil, along with the stiff cone to which it’s glued. Electrostatic drivers operate based on a completely different, more advanced principle. They work by placing a static (non-moving) electric charge on an ultralight film floating between two perforated metal plates. Static cling and repulsion cause the entire film to move by itself when audio voltages are applied across the plates. Because there is no physical contact or interference from coils or stiff cones—and because the film is so thin—electrostatic headphones produce a superior sound, characterized by a lack of coloration and distortion. But since they require a high-voltage power supply and are more expensive, they have historically been less accessible than their moving-coil counterparts.

If we were to write a history of audio companies in the US, Koss would land on the first page. Not only did the Milwaukee, Wisconsin–based company make the world’s first stereo headphone, the SP/3, in 1958, it’s also responsible for the first self-energizing electrostatic headphone, the first dynamic headphone to deliver all 10 audible octaves, and a standard-setting infrared wireless headphone. Over the years, Koss headphones have made it onto Air Force One, into the Smithsonian, and onto the heads of such music icons as Neil Diamond, Tony Bennett, and Pete Fountain. Founder John C. Koss was inducted into the Audio Hall of Fame in 1979 and the Consumer Electronics Hall of Fame in 2000. 

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