According to the HP site soundmax is the driver for the ADI AC97 Integrated Digital Audio Controller.
Try updating the driver from the hp site.
http://welcome.hp.com/country/us/en/support.html?pageDisplay=support
Just put in your computer model into the search engine.
Then see if it has the ability to do line switching in the control panel.
If your computer isn't a HP then i'm way off
.