Does any know how to enable HD Voice on Oneplus One? I am already using CM12.1 using Android 5.11 code base which suppose to support HD voice. But as far as I can tell, the voice quality during a phone call is just normal. I used to able to use Nexus 5 calling my wife's iPhone 5s and the sound quality is much better. I believe that's HD voice but I am not 100% sure.
xda-developers