Ok so my phone started sounding like its in a cave yesterday (after i updated it) ive tried to find a solution but all i could find was people saying to disable the concert hall option in the audio setting (the A50 doesnt have that option or any other option that could be causing the echo) i went through the settings multiple times and found nothing, this update just royally messed up my phone with benefits i'll probably never use, anyways i need help.
I've got the same problem. I know I should turn off the "concert hall" mode, but it's not visible in advanced voice settings. It started just after recent update, on 6.01.2020.
Have you tried the troubleshooting steps mentioned previously in this thread by @userqnO0IdjcFU?
Do you experience these symptoms when you test your device in safe mode?
If your phone is misbehaving, it's possible that a third-party app is causing the issue. To figure out what app is acting funny, you can use the Safe Mode feature. In Safe Mode, your phone won't run any third-party apps. This allows you to easily identity and remove the app that may be causing the problem.
Give this link a try to test your speakerphone with your device in safe mode: