I was listening to one podcast today where a host mentioned the hiss sound coming from their iPhone. He wrote about it online and contacted Apple support to see if this was expected behavior. According to Apple, this was not expected, and they should return the iPhone and get a new one.
A few hours later I threw on another Apple podcast and heard a host casually brush off the hissing as something all electronics do, and there's nothing wrong.
To be clear, one host talked to Apple support and was told this is not supposed to be happening, and another said "this is fine, settle down."
I'm not saying this hiss is the end of the world, god knows there are worse problems your phone could have in 2016, but don't try to tell your audience that this is something that app phones do. This has literally never been a story in the past 9 iPhones, so please, please, please be okay with a tiny thing wrong with a few iPhones. You and Apple will be fine.