LowVolumeCallHearingProblem,
Thanks for providing us with those details. Do you have a case on your iPhone? If so, please remove the case and test the behavior again.
To ensure that we’re covering all of our bases, we have some steps that we'd like for you to perform on your device:
• Set the Ring/Silent switch to ring.
Go to Settings > Accessibility.
Tap Audio/Visual.
Slide the audio volume balance slider all the way to the right.
Go to Settings > Sound & Haptics > Ringtone.
Tap on a ringtone to play it.
Listen to the sound from the receiver.
• Repeat the steps above, changing the audio volume balance slider to the left instead. Next, listen to the device speaker this time instead of the receiver. Does any sound play or is the sound distorted or muffled?
• Do you have Wi-Fi calling or VoLTE enabled? If so, try turning off these features to see if that helps.
Make a call with Wi-Fi Calling
About the LTE options on your iPhone
We hope to hear from you shortly!