Yamaha DTXpress/DTXplorer/DTXtreme

Bry,

Welcome. A factory reset probably wouldn't be a bad idea to start with.

I would expect all the attenuation switches to be down on a standard
setup.  

If you select the trigger edit (shift+trig edit) then page down you
will be able to see what percentage of maximum you are registering
when you hit each of the pads.  If that looks OK (i.e. you can get
near 99%) then you may have to increase the individual voice volume. 
In particular, the hi-hats can be a little quiet.

Keith.