Though your server.cfg may have sv_alltalk as 1, it sounds like either it isn't running, or something is changing it after server.cfg
From server console, type sv_alltalk and enter ... is it still 1?
Either way, o, or 1, ULib and ULX have _nothing_ to do with voice communication by default as a group..
We only control what groups one belongs to (hence why I moved this question to Off-Topic)