Some previous discussion of such hearing device competition and DIY here: https://news.ycombinator.com/item?id=28921244 https://news.ycombinator.com/item?id=28

Some previous discussion of such hearing device competition and DIY here: https://news.ycombinator.com/item?id=28921244 https://news.ycombinator.com/item?id=28921244