[cisco-voip] static on conf calls -- datagathering/troubleshooting

[IT]

I have some users who are complaining about static on their conference
calls. Since this CallManager install is fairly new (6 months), I don't
really have the troubleshooting experience. I have CDR set up, but it
does not seem to be gathering QoS details. In addition, I am unfamiliar
with the other data collection tools that could help me figure out what
is going on...
Can anyone push me in the right direction?

Thanks,
Avidan