Cassette tape

The cassette tape emerged because Lou Ottens had a wooden block in his coat pocket. In the early 1960s, the Dutch engineer at Philips was tasked with designing a tape cartridge for home use—something handier than the bulky reel-to-reel recorders of the time. The wooden block represented his target: a format small enough to carry in a jacket.

The adjacent possible aligned through Philips' manufacturing expertise in magnetic tape and consumer electronics. Two competing teams developed designs using thinner, narrower tape than reel-to-reel systems. Ottens' team in Hasselt, Belgium created a two-hole cartridge under the code name 'Pocket Recorder.' The two-spool design won internal competition, and on August 28, 1963, Philips introduced the Compact Cassette at the Berlin Radio Show.

The initial reception proved underwhelming. Audio professionals dismissed the format's limited fidelity. But Ottens understood something crucial about consumer technology: convenience often defeats quality. He advocated for Philips to license the format to other manufacturers for free, paving the way for cassettes to become a worldwide standard.

The strategy worked spectacularly. By 1966, over 250,000 compact cassette recorders had sold in the United States alone. By 1968, 85 manufacturers had sold over 2.4 million units. The cassette business reached an estimated $150 million. Eventually, over 100 billion cassettes sold worldwide.

The format's cultural impact exceeded its technical specifications. Cassettes enabled mixtapes—personal audio compilations that became a medium for romantic expression and musical discovery. The Sony Walkman, introduced in 1979, made personal portable audio ubiquitous. Boom boxes transformed public space. In developing countries, cassettes distributed music beyond the reach of radio stations and record stores.

Ottens later worked on the team that jointly developed the compact disc with Sony in 1982—the technology that would eventually displace his earlier invention. The cassette's decline in the 1990s and 2000s didn't erase its significance: it had demonstrated that portability and accessibility could matter more than audio quality, a principle that would later drive MP3 adoption and streaming services.

The wooden block in Ottens' pocket became a format that billions of people used to record, share, and carry music. He died in 2021 at 94, having invented the medium and helped invent its successor.