problem with hearing/not hearing one person

[prozackitty]

i am running a ts server on my comp, i have from 5-10 people on. there is one person who can hear all of us but only 3 of us can hear him. its allways the same person that cant be heard, and allways the same 3 who can hear him when no one else can. how ever when im not on they can usualy hear him. its starting to get really annoying. we all have the same version of ts. i have tried to the best of my ability to figure this out of find info on the forum but i havent found any.

[SatanClaus]

read the forum rules, answer the questions and give us a list of the soundcards...

[prozackitty]

ok we all use windows xp, some prof. some home. the cards are mostly sound blaster live, the person that only a few can hear (call him person A) has a sound max audio. he is behind a SMC router. i can hear him and im behind a router so we dont believe the router is the problem. person A has service pack 2, as well as me.