Rainmeter skin used to switch between headphones / speakers. Works in Windows 7.
The AudiosourceSwitcher.exe is based on code from this repo: justinryder/AudioEndPointController.
AudiosourceSwitcher.exe [audio device to switch to]
AudiosourceSwitcher.exe <-- switches to number 0
AudiosourceSwitcher.exe 0 <-- switches to number 0
AudiosourceSwitcher.exe 1 <-- switches to number 1