Koss Corporation has reopened a reimagined factory store attached to its Milwaukee headquarters on North Port Washington Road, transforming what was once a simple repair counter into a small museum celebrating the company's role in inventing stereo headphones. The new space sells headphones just like before, but it now doubles as, in the words of one company leader, a museum and a step into the past.
The original Koss store first opened its doors in 1986, serving for decades as a place where customers could replace or repair their headphones, according to TMJ4 News. That original store closed in 2020, leaving a gap in the company's public-facing presence at its longtime headquarters. Koss has operated out of 4129 North Port Washington Road since 1970, when the company relocated its primary operations and factory store to Milwaukee's north side, a site it has occupied for more than 50 years.
A Milestone Rooted in 1958 Innovation
Koss's story traces back to founder John C. Koss, who launched the business in 1953 as the J.C. Koss Hospital Television Rental Company before shifting direction entirely. Working alongside engineer Martin Lange Jr., Koss created the first pair of stereo headphones in 1958, engineering a design that provided separate left and right audio channels rather than a single blended signal. Martin Moore, speaking on behalf of the company, said stereo headphones made instruments sound like they were positioned around the listener, a leap that changed how headphones are made and how people experience recorded music.
John C. Koss led the company until his death in December 2021 at age 91, leaving behind a business built on that original stereo breakthrough. The new factory store leans into that legacy directly, displaying original headphones built more than 50 years ago and running a short documentary on Koss history for visitors who stop in.
Turning a Factory Store Into a Tourism Stop
Moore said Koss wanted to strengthen its presence in Milwaukee and welcome visitors who may not necessarily be there to buy headphones, a goal reflected in the company's new partnership with Visit Milwaukee. Both organizations hope the factory store becomes more of a destination rather than just a retail counter tucked inside a corporate office. Visit Milwaukee already features Koss alongside other historic local brands, including Harley-Davidson, Miller High Life, and Carmex, in regional tourism campaigns celebrating the city's industrial identity.
The reimagined store keeps modest hours, open Monday through Thursday from 8:30 am to 4:30 pm and on Fridays from 8:30 am to 2:30 pm local time. That schedule fits a company that, according to GlobalData, reported fiscal year 2025 revenues of $12.62 million and operates with a workforce of approximately 28 employees at its Milwaukee headquarters — a lean footprint for a name with this much audio-history weight behind it.
Decades of Engineering Firsts
Koss's product history extends well beyond that first stereo headphone. In 1968 the company released the ESP/6, developed as the world's first self-energizing electrostatic headphone, using a currentless electrostatic charge and ultra-lightweight diaphragms suspended between charged plates. The following year, in 1969, Koss stereophones were installed at every seat aboard Air Force One, with roughly 50 Pro/4 units fitted onto the aircraft to serve as a personal entertainment system for presidential staff and press.
Then in 1984, Koss introduced the Porta Pro, a collapsible on-ear headphone designed to capitalize on the rise of portable cassette players like the Sony Walkman. More than 40 years later, the Porta Pro remains in continuous production, making it one of the audio industry's longest-running consumer products, according to Fast Company.
A Company That Survived Scandal and Cashed In on Meme-Stock Mania
The factory store's reopening arrives against the backdrop of a corporate history that has swung between crisis and windfall. In 2010, former Koss Vice President of Finance Sujata Sachdeva was sentenced to 11 years in federal prison for embezzling $34 million from the company between 2004 and 2009, a fraud that forced Koss to restate five years of financial statements, according to the U.S. Securities and Exchange Commission.
More recently, Koss has drawn attention far outside the audio world. The stock spiked over 1,000% in January 2021 and jumped more than 270% again in mid-2024 during renewed meme-stock trading activity, with company insiders selling tens of millions of dollars in stock during those rallies, as reported by Urban Milwaukee. Koss also notched a genuine legal victory in July 2022, settling a patent infringement lawsuit against Apple over wireless earphone technology for an estimated $10 million to $14 million in net licensing proceeds, part of a broader round of infringement suits the company had filed in 2020 against Apple, Bose, and other major audio brands.
Now trading on NASDAQ under the ticker KOSS, the company is betting that its new store-slash-museum can turn decades of engineering history — and no small amount of financial drama — into a reason for Milwaukee visitors to stop by a headquarters they might otherwise drive right past.
