Devices for amplifying sounds in a listener’s ear date back to the ear trumpets of antiquity. Hollowed animal horns were used first, most likely, the small end placed in the ear and the other end directed toward the speaker so that it could collect and funnel sound, acting like a large, manoeuvrable outer ear. Through the 17th century a wide variety of ear trumpets, or speaking tubes, were in use, made of wood, silver, shell, or horn. By the 18th and 19th centuries, ear trumpets were generally made of brass or other metal, covered with vulcanite (a hard rubber), and painted black to be more inconspicuous. Among famous users of ear trumpets was composer Ludwig van Beethoven (1770-1827), who began suffering from hearing loss at about the age of 28.
The first electric hearing aids came out in the latter 1800s. These bulky devices were of help only to people with minimally defective hearing. Another curious instrument appeared around this time. The acoustic fan was a thin, round piece of vulcanite attached by a wire to a piece of wood, which was gripped by the user’s teeth. Sound vibrations would travel from the fan to the teeth, where they were conducted to the jawbone and then the auditory nerves.
Though Alexander Graham Bell did not invent a hearing aid, his experiments in telephony grew out of his work training teachers of the deaf. Bell’s technology was used to create the first electronic hearing aids in the 1880s; carbon microphones, transmitters, and batteries converted sound into electrical impulses and then back into sounds.
Hearing aids were finally shrunk to a user-friendly size in the 1950s with the appearance of transistors. The first ones fit onto a pair of spectacles; later they were designed for wearing behind the ear.