Some random users found their iPhone 7 makes a hissing sound under heavy load. It is unknown what is the cause since iPhone 7 do not have any fan to cool down its internal component. It is believed the sound is coming from defect manufacturing process and Apple will replace it with a new device. But for those who bought a Jet Black or Black iPhone, 7 might have to wait a bit longer because the model already sold out.
iPhone 7 Hissing Sound:
iPhone 7 Plus Hissing Sound:
My iPhone 7 Plus makes terrible noises when under load. https://t.co/wFM2gImpOb
— Stephen Hackett (@ismh) September 17, 2016
— 9to5Mac (@9to5mac) September 17, 2016