In 1953, John Koss started a hospital television rental company, and although the business prospered, by 1958, Koss -- with only a high school education under his belt -- moved onto his next Big Idea.

Koss, a trumpet player and lover of recorded music, dreamed of listening to music without disturbing others, so he and business partner Martin Lange -- who passed away in late February -- put TV parts inside a makeshift set of headphones made from cut-out cardboard and a coat hanger and invented the first pair of stereo headphones.

At the time, pilots and telephone operators used headphones for communication purposes, but the concept of piping music through a headset was ground breaking.

Today, John's son, Michael Koss, serves as the company's president and CEO.

"Dad put on (the first) stereophones and said it was like being in the band again," says Michael. "The first SP3 stereo headphones for listening to music were invented right here in Milwaukee."

John Koss, who grew up on Murray Avenue on Milwaukee's East Side, played trumpet with a band called, "Johnny Koss & this 12-Piece Orchestra." He raised Michael and his siblings in Glendale. Today, John Koss, Jr. also works for the company.

In 1970, the Koss Corporation moved into its current location, 4129 N. Port Washington Rd. The company employs 80 people locally and the Koss family owns 75 percent of the business. About 40 percent of Koss' business is conducted in Europe, the Middle East, Africa, Asia, South America and Central America.

Koss sells headphones under its own brand, as well as under the Radio Shack name. All Koss headphones come with a no-questions-asked lifetime guarantee.

Michael says the industry changed the most in the early '80s, when people went from using stereophones with hi-fi systems to using them with portable stereo systems like the Walkman. Koss was on top of the trend and introduced the first collapsible headphones that could be used with miniature electronic products.

"Stereophones became a necessity instead of an accessory," says Koss. "If your Walkman or Discman headphones didn't work, then your product didn't work."

This, of course, was good news for the Koss Corporation.

Michael would not disclose the number of stereophones his company has sold over the years, but he assured it was "millions and millions more than my grandmother ever thought my father would be able to sell."

Koss' billboards, visible from I-43, have a 30-year reputation of being humorous and clever.

During college, Michael -- who studied anthropology and art at Beloit College -- worked as a Koss advertising copywriter and helped create a few of the famous billboards including the one featuring the tagline "Betsy Koss" with Betsy Ross stitching the American flag wearing a set of headphones. Also, he brainstormed the "Father Knows Best" campaign featuring George Washington wearing a set of headphones, and "Lettuce Entertain You" with a head of lettuce sporting a pair of stereophones.

Most of the creative billboards came from ad agencies Kloppenberg, Switzer & Teach and Eisenbaum & Associates. Currently, Koss' billboard reads "Koss Training," a play-on-words for "cross training," and features a guy working out on a cross-trainer bicycle.

Michael says his company feels the impact of the recession, but despite the struggling economy, continues to stay afloat.

"We're trying to stay as nimble as possible," says Michael. "We are very customer responsive, flexible and niche oriented."

Michael says most businesses in consumer electronics make many different products, but Koss focuses exclusively on stereophones.

"This makes us interesting," says Michael. "We do one thing, and we do it very well."