I am running X3 . Using a Komplete audio six for interface. The Komplete self tests properly, show in device manager and shows as default output. I continue to get only onboard comp speaker sounds........looking in X3 "preferences"
it shows output drivers for Komplete Audio as well as several others......should I disable the "other" drivers?

Yes. And switch driver mode to ASIO if it isn't already.

thank you. sounds right. will do

 
Switch the Driver Mode to ASIO first, click Apply, and then go back and select your audio interface in Devices.
 
And, while not directly related to your issue, if you are changing around your audio devices for Windows -  I would also recommend you NOT have your audio interface additionally specified as your Windows default audio device, so you can avoid any conflicts between multiple applications trying to get at your ASIO drivers at the same time.  (Windows sounds, Windows Media Player, YouTube, etc).
 
Some folks run a separate set of computer speakers out of the green mini jack in the back of the computer, to hear regular sounds, and then just use the audio interface for Sonar or other high-end music applications that will run by themselves.
 
Others run a stereo splitter out of the little green audio jack of the computer, and split the signal into 2 feeds that they then run into the audio interface, so that even the Windows sounds go through the presumably nice speakers connected to the main outputs of the audio interface.
 
Others completely disable the on-board sound on their computers (sometimes, some folks have conflicts/problems for some reason, so they work around them by simply disabling the on-board sound).
 
Another option is also available, IF your computer display happens to be an HDTV.  You could set the HDTV as the Windows default audio device, if you have an HDMI connection between the computer and the TV.
 
Lots of choices, 
 
Bob Bone