Best VOIP audio settings - problems with participants hearing each other

Hi everyone. I have searched around a bit but can't seem to find recommendations on the very best settings in Adobe Connect (and/or recommendations on server location) to get the best possible VOIP experience for participants.

While little dropouts in VOIP audio occur (and can be expected when participants leave email open in the background and the internet gets congensted for a second etc...) we fairly regularly have the problem that participants on VOIP cannot hear each other well.

For example, today I hosted a session in Brisbane, Australia. I could hear two participants - one in Sydney and one in Perth - quite clearly. But they could barely hear each other. This happens quite a bit - I am loud a clear to the participants as the host and presenter, but they often struggle to hear when I unmute a training participant to ask me a question via audio - I often end up having to repeat what they said to all the other participants.

Any tips on how we can strengthen the VOIP audio between participants themselves? This is especially important when we want to use break-out rooms. Break-outs work great when everyone is on the phone, but when the group is on VOIP, often participants complain that they couldn't hear each other very well in their breakouts.

I have already had participants run the Audio Set Up Wizard, close software and use a headset - all the basics are covered. And, besides, I can hear them loud and clear. Its the participant to participant audio which is the problem. Any tips on which settings to have in the Preferences box or anything else we could be doing would be great.

Many thanks,

Dave