Blurry sound when calling
My microphone is blurry a lot of the time not on my phone but on the other end
sometimes my phone also sounds very robotic and the microphone cuts out completely
iPhone 7, iOS 12
If the microphones on your iPhone aren't working
If you can't hear a person on a call or voicemail or if the sound isn't clear on your iPhone
Also want to check your LTE settings.
Settings > Cellular > Cellular Data > LTE > make sure set to Data only or off. You do not want Voice LTE selected and test.
Still not resolved?