Headphones emerged due to the need to free up a person’s hands while using a telephone. The technology behind hands-free headphones came in many iterations. A British company called Electrophone created the first headphone in the 1890s, which allowed their customers to tune into live broadcasts from theatres and opera houses across London. Listening to the performances required subscribers to connect a pair of massive earphones with a long rod underneath the chin.
In 1891, Ernest Mercadier patented a pair of in-ear headphones. Nathaniel Baldwin invented the prototype phone headset in 1910 in response to his inability to hear sermons during worship services during the week. Before amplifiers were developed, the only way to listen to electrical audio signals before earphones was through telephone receiver earpieces. Baldwin offered them for testing to the US Navy, which promptly ordered 100.
Moving iron drivers are used in these early headphones, and either single-ended or balanced armatures are employed. Voice coils were wound around the poles of a permanent magnet near the diaphragm in a single-ended speaker. Sound waves are created when the audio current is passed through the coils, varying the magnet’s magnetic field, thereby exerting a varying force on the diaphragm, causing it to vibrate. Since there was no damping needed due to the requirement for high sensitivity, the frequency response of the diaphragm had prominent peaks due to resonance, which resulted in poor sound quality. The headphone of early powered radios was part of the vacuum tube’s plate circuit and carried dangerous voltages. John C. Koss, an audiophile and jazz musician from Milwaukee, developed the first stereo headphones in 1958.
Below are some old vintage ads of headphones from the 1950s to 1980s.