You must admit that some of today’s technology advances are very useful. Take hearing aids, for instance. Today’s micro-miniature hearing aids can hide inside the ear canal. A few sightly larger ones with more capabilities hide discreetly behind the ear. Hearing aids worn by our ancestors were not always so discreet.
The earliest known hearing aid, called an ear trumpet, was described by Belgian scientist and high school rector Jean Leurechon in his book Récréations-Mathématiques, in 1624. The book described how to make your own ear trumpet as there were no manufacturers of the device at that time.
In the late 1800s, Thomas Edison, who was hard of hearing, found that he could not use Alexander Graham Bell’s new invention, called the telephone. The fact that he could not hear sounds from the telephone spurred his interest in improving it. This led to his 1878 invention of the carbon microphone for telephones, which, unlike Bell’s device, amplified the electrical signal.
In 1907, Lee De Forest of the Western Electric Company invented the first vacuum tubes, and the electronic amplification of sounds became possible. However, the company’s first “hearing aid” in 1920 was anything but portable: it weighed 220 pounds and was the size of a filing cabinet. That hearing aid was best used when placed beside the user’s living room easy chair; from his or her chair the user would hold a single earphone that looked like an old-fashioned telephone receiver. (Headphones were not invented until a few years later). For many wealthy deaf users, this was the first time in years they could participate in family conversations.
In 1938, the Aurex Corporation developed the first wearable hearing aid. A thin wire was connected to a small earpiece and then to an amplifier-receiver that clipped to the wearer’s clothes. The receiver was wired to a battery pack, which strapped to the leg.
By the early 1950s, hearing aids had been “miniaturized” to fit into a man’s shirt pocket. I well remember my uncle wearing one of these. It contained miniature vacuum tubes, and it consumed expensive batteries quickly. My uncle reported that he was frequently bothered by the rustling sound of his clothing as amplified by the hearing aid. Then he would smile and also comment that the hearing aid also was a great excuse for not listening to his wife. “I don’t know, Honey, I think the battery died.”
By 1957, hearing aids were small enough to fit into eyeglass frames. Lee De Forest himself, by then 84 years old and hard of hearing, appeared in ads in 1957 endorsing the product, saying, “It overcomes all of the objections I previously had to wearing a hearing aid.”
Of course, miniaturization continued. Even better, digital processing of the audio appeared by the late 1980s, and the problems of background noise were reduced. Today people suffering from hearing loss have many tiny solutions to choose from. If only Grandpa had one of these available when he needed it.
For more information, read Hearing Aids and the History of Electronics Miniaturization [IEEE Annals for the History of Computing, 2011, Volume 33] by Mara Mills at http://goo.gl/2JXHi1.