Type "Volume" in the Search box for Keyboard Shortcuts.
BOOM, that worked! The different names for utilities keep throwing me off. For anyone else wondering:
Decrease Clip Volume [ [ Decrease Clip Volume Many Shift+[ Shift+[
Thanks for the help!!
You might try spending a little time going over the Keyboard Shortcuts dialog box. If there are any commands you don't understand, you can check them out and see if they are similar to commands you might know in another NLE.
One neat little trick that surprised me is that you can select a whole range of clips and change all their volumes at the same time with this shortcut.