First, it was iPhone 7 Home buttons and capacitive gloves, now it's iPhone 7 making a "hiss" or "buzz" sound. Every year, the tidal wave that is iPhone launch attention sweeps up all sorts of "gates" in its wake, and it can be difficult and confusing to sort the real from the imagined.
We've now spent almost a day testing both iPhone 7 and iPhone 7 Plus, as well as the last two generations of iPhone, all recent iPads, recent Macs, peripherals like routers, and other electronic devices. And here's the deal:
They all make the same noises, and all to differing degrees. I initially thought iPhone 7 Plus might be louder, but after putting a series of devices through high-intensity CPU/GPU activity, which pulls much more power than normal daily use, they all sounded roughly the same. That includes the MacBook Pro I'm typing this on right now.
It also makes sense, given the people who noticed the noise did so while their new iPhones were restoring, which migrates libraries, re-indexes data, and otherwise puts the system through heavy load.
Since many people have now reported hearing the same sound from other devices across a wide range consumer electronics and brands, and hardware engineers around the internet have commented and tweeted explaining what the sound is and why it's not only normal but expected, it seems highly likely nothing out of the ordinary is going on. (I'd say "almost certainly", but I try not to mistake my writing for an engineering degree!)
Perhaps there's something about the new iPhones that makes the sound louder and more noticeable, or perhaps it's because everyone is hyper-vigilant following the Galaxy Note 7 recall.
Regardless, there doesn't seem to be anything to be concerned about, not with the processors, the batteries, nor the radios. So go back to setting up your new iPhones, and enjoy!
Updated to reflect additional testing and information.
