Hi,

The vMix Call web sites do not actually process or handle the audio.
Instead, they send messages back and forth between the browser and vMix so that each end can establish a direct feed (via WebRTC).

This means any audio issues are going to be due to either the audio devices on the system, or the browser itself.

You mentioned the advanced.vmixcall.com exhibiting the issue but vmixcall.com does not.
Assuming you have not changed any of the audio settings on advanced.vmixcall.com that leaves only the audio device selection as the possible cause.

vmixcall.com uses the default audio device as shown in the browser settings, while advanced.vmixcall.com allows you to change this.
My guess is perhaps a different audio device was used, maybe something like an onboard laptop mic, instead of the default device, explaining the difference in audio, so that would be the first thing to check.

Secondly, it is strongly advised to always use headphones and make sure no speakers are turned on.
This is because the browser handles all the echo cancellation and it doesn't always do a good job.

Hope this helps.

Regards,

Martin
vMix