Q: metallic sound

Hello there, JEPEDeWinter.

The following Knowledge Base article offers up some great troubleshooting steps for audio quality issues on the receiver of your iOS device:

iPhone: Receiver and call audio quality issues

http://support.apple.com/kb/ts5196

Follow these steps to resolve the issue:

1. Increase the volume during the call.
2. Make sure nothing is blocking the receiver. If you're using a protective case or display film, remove it and try again.
3. Make sure nothing is plugged into the headphone jack or the dock connector.
4. Check the receiver opening to see if it is clogged with debris. If necessary, clean it with a clean, small, dry, soft-bristled brush.
5. Try another location with better signal. If the audio issue happens only when on a call, it could be due to the location.
6. If the iPhone is paired with a Bluetooth headset or a car kit, try turning off Bluetooth on your device. Learn more about troubleshooting Bluetooth connections.
7. Restart the iPhone.
8. Make sure your device is up to date.
9. If the issue is not resolved, contact Apple Support.

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.