microphone allways turned on

I don't have an Xbox but I think you can go to Settings -> Kinect and disable that part of it.

Also for headsets I think in the Privacy Settings "text and speech" you can set it to friends only I believe.

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Posted in wrong section? meant for PC?

http://www.crashwiki.com/pvz-garden-warfare-disable-chat-disable-mic-use-push-talk-use-voip/

Right click speaker icon in system tray.
Select Playback Devices.
Select a Playback Device other than what you use for sound output.
Right click it and select Set as Default Communications Device.
Hit OK.
Left click on the speaker icon in the system tray.
Click the icon below the slider on the device you chose to mute it.

Do the same for your Input.  Change Skype, Teamspeak, Raidcall, Vent, whatever to use the correct devices.

Oh this is for xbox area. i need to find the pc area lol

It's a design oversight. A pretty major one, so I hope they'll fix it soon.

Right click the speakers icon on the bottom right in Widows, then go to recording devices. From there you can turn off your microphone. If you want to automatically mute everyone in game, go to the list of playback devices in Windows, right click one that's always disabled, and make it the default communication device.