Audio

I use Zoom regularly (On PC Windows 10) and have no problems usually concerning the other person/s hearing me when on a Zoom call.

But each week I hold a Zoom meeting where I use Computer Sound share (in Advanced). Some of the participants have difficulty hearing me speak, unless I hold a mic to my mouth (Audio-Technica) and some have difficulty hearing the music (on PC Computer) I play unless I turn it up to what is uncomfortably loud for me. But they have no difficulty hearing a speaker (on PC Computer) when I play.  I have checked my settings and can't see what the problem might be.  I have asked them to check their settings also and the same response applies. What to do? I would welcome any suggestions.