One need to perform below mentioned steps to enable audio mapping with Remote Desktop Terminal services:
1) Click on start -> run.
2) Type tscc.msc and click on OK button.
3) On the left side you should see that "Connections" is selected, on the right side you should see, under the "Connection" tab, RDP-Tcp. Right click that, and press properties.
4) Go to the Client Settings tab, and under "Disable the following:" one will see "Audio mapping" checked. Please uncheck it.
5) Click on OK button to complete the process.