I have found a solution that works for me to correct the low volume issue on Duo calls.
My mobile (cell) 'phone connects automatically to my landline 'phone via bluetooth when I am at home. If I break the connection by manually by either disconnecting my mobile from the landline, or by turning off bluetooth on my mobile, then the sound returns to full volume for both sides of the Duo call!
I have tested this method by turning bluetooth off before a call and then during a call, with success in both instances. In fact bluetooth can be left on, as long as it is not connected to another device.
Low volume has been a problem for me on Duo video calls for some time, and I am pleased that this solution works for me. I will be even more pleased if it works for other people. If you use bluetooth earbuds or headphones, try making a Duo call without them and see how you fare!
Hopefully Google reads my post and corrects the issue in the next release.
Samsung Galaxy J5 2018
Anonymous, 26 Mar 2018You could also revert back to normal calling since google will kill this service eventually ju... moreIf it adds abilities to sell your person as a commodity they'll keep updating it, just like Facebook.