You. are. the win.
This is great. I have the "line in" (xm) is is louder than mp3 problem. PLUS I have an internal mic (laptop setup) that gives off a high pitched squal if turned up. With this I can set the mic to 0%, and tie everything else to the main volume, with the % for the line in to make XMmp3 transition smooth as you stated.
THANK YOU!!
-arebelspy