XPS 15 9575 microphone not working well

On Zoom other participants either can't hear me at all, say I'm too soft and garbled.  I've checked all settings, played with the Maxx Audio Pro, recorded with Voice Recorder app (recording is soft and often buzzy) and nothing seems to help much.  I spent a few hours with a Dell tech a few days ago and he didn't really know how to fix it; we uninstalled and re-installed drivers but ended with him agreeing that the mic was in a bad spot and not good. I got this 2-1 a month ago to use for remote meetings with clients.  Now I'm just frustrated!  I'd appreciate any input or similar experience.  Thanks.