Do you mean it plays back what your mic is picking up through your headphones? If this is the case you could try disabling "listen to this device" in Windows audio devices if you are using windows that is. To do this, simply right-click the little speaker icon on the bottom right of your taskbar and select the "recording devices" option. From here right-click on the microphone you are using and go to "Properties" and select the "Listen" tab. There will be a checkbox called "Listen to this device". If this is selected, unselect it and press "Apply". That will hopefully solve your problem.