You can thank your old Sony Walkman for ushering in the era of portable entertainment

This story is part of The Butterfly Effect, a special Spark series about technological advancements that had a much larger impact than most people anticipated.

Sony's first Walkman wasn't technically a new invention when it first hit the market in 1979.

"It was putting a cassette deck and a pair of headphones plugged in [together]. That's all it is," Michael Bull, a professor of sound studies at the University of Sussex in the U.K., told Spark host Nora Young. 

Cassette tapes had been around since the 1960s. In the late '70s, Sony released the Pressman, a clunky tape deck with voice recording functions and built-in speaker meant for reporters. 

But Sony's then-chairman Akio Morita had greater ambitions. The Japanese company stripped away the Pressman's speaker and recorder, paired it with a slim pair of headphones and gave it a now-iconic blue-and-silver deco, accented with a fluorescent orange "line in" button. 

The Walkman model TPS-L2 exploded in popularity, and went on to change people's relationship with music and how they listened to it. It also set the blueprint for portable devices, traces of which remain in the design of our smartphones today. 

TV producer and vintage tech enthusiast Bohuš Blahut vividly remembers when he first tried using his cousin's Walkman. The Chicago native, then nine years old, was visiting his relatives in Canada. 

"When I put it on, I couldn't believe the fidelity. It was just so much better than anything I'd ever heard that was portable," he said.

Sony sold millions of Walkmans, helping cassettes overtake vinyl discs as the musical medium of choice. The brand name continued on as consumers migrated to using compact discs, and eventually digital MP3 players.

The Walkman brand had all but fizzled out by the 2010s, as the digital music market was overtaken first by Apple's iPod, and later, smartphones.

But it remains a well-known name and product, thanks in part to its frequent appearance in nostalgia-fuelled pop culture, from Stranger Things to Marvel's Guardians of the Galaxy.

"I think it's become one of the shorthand icons for the '80s, in the same way that if you go into a party store and you say, 'I want to have an '80s party,' they'll have like a banner that has Pac-Man and a Rubik's Cube on it," said Blahut.

Taking a Walkman outside on a run took the music-listening experience from the privacy of your family room to the public sphere.

It not only changed where we listened to music, but how we listened, too. With those headphones, you became an audience of one, even in a crowd. That could be empowering, especially to youth at the time.