Remote Desktop microphone redirection
INFORMATION TECHNOLOGY 2013/10/19 08:48
Install and configure the microphone on the local PC and set redirection at Remote Desktop Connection

Remote Desktop Connection microphone redirection
Allow audio recording at host
HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp
fDisableAudioCapture REG_DWORD 0x00000000
Allow audio recording at Group Policy
Computer Configuration \ Administrative Templates \ Windows Components \ Remote Desktop Services \ Remote Desktop Session Host \ Device and Resource Redirection
Allow audio recording redirection Enabled

Additional information