Yamaha DTXpress/DTXplorer/DTXtreme

I tried my idea of using a blank song, but it doesn't work.  The
DTXpress won't let you have a blank song.  Also, starting a song with
a pad doesn't start the click anyway, even if the song settings are
for "auto click".  

The nearest I could get to what you want was to create a song with the
"notes" of the song being your click pattern.  Then you can assign
that to a pad.  However, because it is not a click it will be mixed in
with your drum sounds.  I don't think you can do what you want with
the DTXpress.  What you need is a metronome with a big on-off button
you can hit with a stick!

Keith.