Agreed, that last 5% of fine tuning frequency bands etc you need a professional, but if you were going to roll out $12 hearing aids to all of the low income are

Agreed, that last 5% of fine tuning frequency bands etc you need a professional, but if you were going to roll out $12 hearing aids to all of the low income areas of the world 1 billion people at a time, using an android app on a cell phone you could probably give a lot of people back their hearing. Volume levels could be hard-limited in software, and people who need to exceed the preset limits could be referenced to a senior technician in those 5% of cases or whatever it might be. Being able to hear even every other word would improve quality of life of many people. Probably one in three words is the acceptable limit of "good enough" where suddenly they are worthwhile to hassle with. My grandparents now hate family gatherings because they might understand only one in five sentences spoken directly to them because of hearing problems and the quality of the hearing aids they're able to afford with their insurance.