speech intelligibility

as participant in zoom meetings I have no control on the audio quality from others.

Often there is an echoing effect that muffles speech. Speech is clearer listening through earbuds, but using a sound-bar some speech is inintelligible; the higher the quality of my audio equipment the worse the problem becomes.I believe that the issue is that earbuds selectively transmit the mid-frequencies, while HiFi audio equally amplify bass and treble. 

Once Windows included a mixer utility that allowed enhancements for speech, but no more. And searching for sound mixers brings up only utilities to control sound recording, rather than for sound reproduction.