I got a new 6s a month ago or so (a jump up from a 4s). Ever since I have gotten complaints about sounding muffled during calls. The other end sounds nice and crisp to me, but they say I sound muffled.
I have tried...
-case on or case off, doesnt matter
-backed up phone and wiped it clean, no change
-restored from that backup, no change.
-turned off noise cancelling, no change
-hard reboot, no change
-tried holding the phone a few different ways, different ears, no change.
-voice recordings sound OK to me, but not fantastic
I am at a loss and am fairly certain this iphone is bad. Any other ideas? If not, next step?
Contact Apple (by phone or if you have a store nearby go to them). They will check your device and if it's a defect they will replace it under warranty. Would suggest going directly through Apple while under warranty.
An update to this, When using a 3rd party app to make calls (via wifi) like Cisco Jabber or Facebook Messenger I sound crystal clear.
So definitely not a physical problem. Definitely a verizon/cellular issue.
I just re-enabled HD calling to see if it's any better.