Echo on messaging voice calls (whatsapp, kakaotalk)

[strifej]

Hey, did a search but didn't see anything. I have a G7 running ULM20e (sprint cross flashed).

When I'm on a call using Whatsapp or Kakaotalk, the other party can hear their own voice (echo). I never hear any; it's perfect for me. When I switch to speakerphone and keep the volume low, then they DON'T get the echo. With earphones plugged in (iphone style earbuds), they still hear the echo.

Does this sound like a software issue?

I installed a mic app to record voice/sound and when I speak into it, it's fine. No echo, so the mics are operating properly.

Weird, and the gf is getting annoying.. sigh

 

[strifej]

Posting my fix for future reference. After some research and lots of software testing (tried 3 differen roms, Oreo and Pie), I believed it to be a "hardware" issue. On youtube, I saw a video that described a fix and I basically did that: https://www.youtube.com/watch?v=FkcxzmCPFWw

I took soft foam and covered the areas around the bottom microphone with it. Both underneath the plastic shield (boombox speaker) and above (just under the back panel). It has reduced the echo to 10-15% of the amount before, but not completely eliminated. I think I can live with that for now.