I've been having this problem for over 3 weeks now, and I finally found the solution.
When using your microphone, you will get kicked out of the server with an error "Voice packet unwanted samplerate (cur = 24000, want = 16000)"
The solution is simple, although I do not know what exactly causes this problem the solution is to simply roll back your STEAM (not your 1.6 as there are no beta or new updates for it).
You may be facing this issue because you have participated into Steam Beta.
To roll back your steam from beta to a proper build, click on your steam settings and select the tab "Accounts" then find Beta Participation and click Change, select "NONE - Opt out of all beta programs"
Your steam will restart and will download and install the latest public build, the problem should not reoccur after that.