I'm the host. I share my screen with video and sound. Participants say the sound is much reduced from the my voice. My system in Windows 10, I9 processor Dell OptiPlex 7780 All-in-One What am I doing wrong? Thanks!
You may be doing nothing wrong - could be a configuration issue.
Run the built-in Windows 10 troubleshooters. The troubleshooters may find and fix something.
Failing that then physically verify that the microphones and headsets are working correctly.
Start by swapping microphones, headsets, etc. with other known working microphones and headsets. Try your current microphone and headset on another known working computer. With and without Zoom.
Determine if the problem follows the microphone and earphones or stays with the computer.
Either way there is still more that you can do:
First, go to Zoom's website and search for Zoom audio options etc. that you, as host, can control on your system. Ensure that the settings are indeed as they should and/or as you expect. Some conflict or contradictory setting is a flag.
Second, right click the small speaker icon usually located in the lower right screen corner. A 5 item menu should appear. Likewise explore all of the menus, windows, tabs, and properties that are presented.
No need to make any immediate changes. Again the objective is to just examine the current settings and determine if they are as you expect. Anything otherwise can be addressed by making one change at a time to see if the problem is resolved.
If nothing is astray, then manually download the applicable audio and video drivers. Reinstall and reconfigure.