iphone 6s mic volume low. any way to adjust it?
I just upgraded from my old iphone 4s to an iphone 6s plus. Brand new, not refurbished. My parents are both elderly and hard of hearing, but use hearing aids. When I call them from my new iphone, I have to practically shout for them to understand me, yet the old 4s worked ok. My sister also has an iphone(though I don't know which model) and says she has the same issue. This is a real problem for me, as I mostly use my cell phone, so that if they need to reach me in an emergency, unless I am at home with my landline, they cannot hear me very well at all. This could become a big problem in a crisis.
I tried to search apps, but the only things I can find seem to be more geared toward boosting the speaker on the iphone for playing music, not increasing the gain on the mic. Does anyone know of any such apps which could help this, and if not, is there any way to submit such a suggestion to Apple developers for a future update. I have searched online and I am NOT the only person who has had a low volume mic issue, and this has been an issue for a while, it seems.
iPhone 6s Plus, iOS 9.1