Chosen Solution
Ringtone volume is very low. On call it is very quiet
Clean out all the speakers on the device with a toothbrush and some alcohol, and check the quality of sound then. Try going into Settings > Sounds and Haptics, and dragging the Ringer and Alerts slider around a bit to see if it changes the volume of the ringer. If nothing else seems to be helping and you’ve tried factory resetting the device, perhaps take it into a service store for a diagnostic or if you’re able to yourself, replace the earpiece speaker and see if the quality of audio coming through on calls improves.
