Windows 7 and later versions of Windows do not allow you to select more than one output sound devices. This design model has be chosen by Microsoft in such a way that makes it harder for users to change the default output device. In order to change the output sound device, you have to go through many settings and windows accessible from the Control Panel. This is all very frustrating if you have more than one output sound devices and want to switch through them. Sometimes the utilities that come with the sound device drivers are helpful (for example, Realtek sound devices come with Realtek HD Audio Manager), but not everyone is going to use them. If you want to quickly switch through output sound devices in Windows, then you can use the free SSD (SetSoundDevice) utility.
You should not confuse SSD with Solid State Drive as both are different things altogether. SSD in our case is a free software that helps you to switch sound devices automatically without going through the rigmarole of the going through the Control Panel settings.
You can download SSD from the website of its developer. The download is available as a portable application. You can also download its source code (written in AutoIt Script) if you are interested in that. After downloading, unzip the archive to a folder and run SSD.exe from there. It would show you your usual Windows sound device settings along with the SSD window from where you can select a default output device.
All you have to do is select an available device from the drop-down list and click on the Change Default Sound Device button to switch to that device. If you have only one device listed in the drop-down list, then you perhaps have no other device to switch to.
SSD is not designed to be used primarily with the GUI, but it can be used from command line interface with more flexibility. You can give command SSD.exe followed by an integer to select that device. For example, SSD.exe 1 selects the first output sound device, SSD.exe 2 selects the second output sound device and so on.
So if you work with sound editing and have to switch through output sound devices very often, then SSD can prove to be very useful and productive. It can save you from multiple mouse-clicks and going through a series of settings.
You can download SSD from http://funk.eu/ssd/.