Yamaha DTXpress/DTXplorer/DTXtreme

ok select the pad you want to turn into a midi sound and press voice.
Scroll through with page till you get to:

Kit*IN=open V=-
Ch=10 GateT=0.3s

then change the Ch=10 to Ch=1

after that keep scrollign through with page till you get to

KIT*PC  Ch 1= off
PC= 1 M= 0 L = 0

then change the Ch 1= off to ch= on
and then scroll through the 128 GM Midi voices
by slecting the PC= 1 thing, and using select to scrol lthrough the 
sounds.

and there we go. Hope you understand.