Strange problem with only one user

[sgz22]

One of the users of our clan server can only be heard by about half of us, but to the other half of the people in the server can not hear him at all. His light doesn't even show on their systems, but everything is fine with the connection I have with him. Any ideas would be great. We have tried changing codecs, channels, reconnecting, ect... nothing seems to work. Please help.

[SatanClaus]

I'm suffering from a lack of information...

which system / os do you all use, which TS-Versions???
directx?
latest drivers?

...

cu
SatanClaus

PS: how do you think we could help you if you basically just tell us that there's a problem? :p

[sgz22]

OS = Windows XP
TS = newest version
DX = 9.0
All the latest drivers

I just don't know where the problem is. Is it the users that can't hear him, or is it on his end, or is it a server problem? I'm just not sure where to start.