As hearing aids go quite a bazaar device. Commissioned by a Portuguese King in the early 1800’s, the Acoustic Throne remains one of the worlds most interesting devices and quite remarkable technology for its time. Check it at the following link:
The link goes to the story of Joao’s Acoustic Throne, published July 28, 2015 by Hearing Health and Technology Matters, LLC, Tuscon, Arizona. Linked by permission.