If you recently updated SteelSeries Engine and are having an issue with your microphone, please take the following steps to fix it and restore microphone functionality:
1) Open Control Panel and navigate to Device Manager.
2) Expand the Sound, Video, and Game controllers tab
3) Right click the Siberia Elite / 650 as pictured in this link: Siberia Uninstall.
4) Click Uninstall.
5) Unplug the headset from the PC, wait 10 seconds, then plug it back in.
The issue should be resolved at this point. If not, please file a ticket with SteelSeries Support.