NOTE: This article assumes your sound works fine in KDE 4.x, but you want to switch between your sound card on your motherboard, HDMI Video Card, and an external audio device like a USB headset very quickly.
I have not been able to find a way to create a script that could be incorporated into a plasmoid app, or menu shortcut, but I used the following step by step details to create a Quicklaunch Launcher with the Quicklaunch Plasma Widget that opens the Phonon Audio Device Chooser/Configurator directly instead of finding the System Settings Icon, then clicking Multimedia, then clicking on Phonon.
Go to the bottom of this post for helpful links such as adding plasma widgets which the next 2 steps show you one way to do it:
Step 1) On your keyboard, with all windows minimized, hold down the ALT key(right or left one) and then quickly press and let go of the D key and as you let go of the D key, you can also let go of the ALT key. This will bring up a bar loaded with plasma apps to choose from. (Optionally you can then quickly press and let go the Q key once which will then only show the apps that start with Q)
Step 2) Find the Quicklaunch app (NOT THE Application Launcher), then left click and hold on the Application Launcher and drag it to where you want it for example one of the Panel(s) or onto your Desktop.
NOTE: THE NEXT STEPS SHOULD BE PRINTED OUT OR MEMORIZED BECAUSE IT IS HARD TO SWITCH FROM THIS WEBPAGE AND THE WINDOW THAT POPS UP IN THE NEXT STEP
Step 3) Right click the Quicklaunch app and then left click the Add Launcher option. This will open a small window. NOTE: LATER YOU CAN REMOVE UNWANTED LAUNCHERS BY LEFT CLICKING ON REMOVE LAUNCHER INSTEAD OF ADD LAUNCHER BUT BE CAREFUL WHICH LAUNCHER YOUR MOUSE CURSOR WAS ON WHEN YOU RIGHT CLICKED
Step 4) In the small window that popped up, type the following commands between the quote marks (") but not including the quote marks and then left click OK: "kcmshell4 kcm_phonon" (NOTE: There is a space between the commands) This will open a slightly bigger window.
Step 5) There are several Tabs at the top of the new window including General and Application (We are not doing anything with the other Tabs) Make sure you are on the General Tab by left clicking the Tab with the word General on it. You will see an icon just below the word General. (You can change the default icon by clicking on the icon and going through a process of choosing a different icon) Also, to the right of the icon you will see the command kcmshell4. You can change that to anything you want, but I suggest you change it to Phonon because that is the program that allows you to change audio devices quickly.
Step 6) Left click the Tab with the word Application on it. At the top you will see the word kcmshell4 again. You can change that to anything you want, but again, I recommend you use the word Phonon.
Step 7) Click OK
Step 8) Click the new Quicklaunch launcher you just created and see if it works.
For all kinds of information on plasma widgets, click this link:
For instructions on choosing another icon, click this link: http://ubuntuforums.org/showthread.php?t=1801703#5
Good luck and email me at "TrekJuny [at] Gmail [dot] com" if I you have questions for me!