Trying to learn about hearing aids and "gain"

[Um_bongo]

It’s literally searchable on this site:

If someone has 70db HL and gets 70db HA gain, does he hear 0db?

From a previous thread: OK, it comes down to the application of gain. First you have to understand that these numbers we throw around on here 80-90-100 dB aren’t a linear scale. To put it simply, if one speaker puts out 80dB and you put another speaker right next to it you produce a whopping 83dB. So a doubling of ‘power’ equates to a 3dB rise in measured output. The next thing to take into the equation is that there’s a reasonability test applied to gain which forms the basis of all gain cal…