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Mistakes were made!

For all the advancements we have enjoyed in the hearing aid industry over the past century, and for all the leaps we have made in improving the lives of people with hearing aids, not every voyage is a fruitful one. In this edition of our throwback Thursday series from The Eriksholm Collection, we look at one of our most famous mistakes. Stay tuned, there is a little bonus at the end!
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The Model 566PC

What happens when you put a microphone right next to its speaker? You get that famous beeping white noise, commonly referred to as ‘feedback.’ That is a lesson that someone should have told the Oticon engineers in 19xx, when development began on the Oticon Model 566PC, a behind-the-ear hearing aid, which sought to improve the quality and clarity of the hearing aids of the day, by bringing the microphone closer to the ear. To accomplish this, the engineers added a tube to the hearing aid, this one carrying the microphone. The reasoning was, that the closer you bring the microphone to the ear, the more accurate the sound becomes, especially if you can pick up the sound from in front of the ear. The idea ultimately died when in production, when engineers realized, that the hearing aids were giving off excess amounts of feedback. 

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The Ear Jewel

In 1964 Oticon entered the market for in-the-ear hearing aids. Because Oticon did not have the sufficient expertise to manufacture these hearing aids, it was decided to use an original equipment manufacturer, an OEM product. The equipment was bought via the company Dahlberg, who – at the time – produced a modular ITE product, model Miracle Ear V. Oticon sold the product re-branded as the Oticon Ear Jewel. The hearing aids, however, never took off, primarily due to the inconsistent lifespan of the batteries. One battery would last 20 hours, another 20 minutes. When the late, former Oticon president Bent Simonsen visited Eriksholm Research Centre few years ago, he had an interesting take on the Oticon Ear Jewel. Upon seeing the hearing aids, he let out a very audible chuckle.

When our in-house historian, Claus Nielsen – whom we thank very much for making these articles possible – asked Mr. Simonsen about his audible reaction, he said: “I remember these hearing aids. We bought about 100 Ear Jewel hearing aids from Dahlberg. We sold 100 Ear Jewel hearing aids. We got 100 Ear Jewel hearing aids back from the customers.” 

Not quite a success, by any means, but a learning experience nonetheless. And so, in the spirit of Thomas A. Edison, we remember his famous quote in the 1994 World Development Report: “I have not failed 10,000 times. I have successfully found 10,000 ways that will not work.

Bonus: Mistakes Found in Research

In most cases, a product fortunately will not make it as far as the Ear Jewel or the 566PC did, before a flaw is detected. Such was the case for the first attempt at the Oticon DigiFocus, the world’s first digital Behind-the-Ear hearing aid. While the hearing aid went on to become a huge success, getting to a finished product was not an easy task, and part of that story played out at Eriksholm Research Centre. 

The goal was for DigiFocus to process all sound digitally, using a small signal processor chip in the hearing aid. Developing a prototype for such a hearing aid would be a world’s first, and it took a large engineering team almost six months to produce about 50 copies of the prototype to be used in a double-blinded study at Eriksholm. The purpose of the study was to determine the effectiveness of digital hearing aids. When the prototypes made their way to the research centre, it quickly became clear that they were flawed.

The digital chips seemed to have an error, due to which they would constantly give off a low beeping noise. When the casing of one of the 50 hearing aids was broken open, it became apparent why. Out of the close to a million transistors that goes into a hearing aid, someone had accidentally added a faulty connection between two transistors on the chip; as a result, the chip could not entirely shut off sound, and thus, it kept producing an ambient beeping tone. The error was immediately taken to the engineers, though it became clear, that the project would either have to be postponed for 6 months in order to remake the prototypes, or a solution would have to be found really quickly. 

Fortunately the latter became an option when a small American company offered to simply weld every single one of the hearing aids to remove the extra transistor. 50 hearing aids were shipped across the Atlantic, and – lo and behold – 50 working hearing aids came back home. The study was conducted at Eriksholm Research Centre, and soon after, the DigiFocus went into production, to become the success we all remember today.

The Eriksholm Collection charts the history of hearing aids and hosts a unique collection of mechanical, electrical and electronic instruments. As one of the most complete collections in the world, it provides an impressive overview of the advances in hearing-aid technology over the last century.