Sorry if this is a dumb question, but I'm missing it in FCX. I'm working on a multiclip and trying to quickly cross my audio sources only. Any work arounds, other than manually tweaking every audio intersection?

Try this:

Final Cut Pro X transition plug-in: Sound only | blog.alex4d.com (http://blog.alex4d.com/2011/07/11/fcpx-transition-sound-only/)

Success. Thank you! Commentary... professional video editing software should include an audio crossfade.