Yamaha DTXpress/DTXplorer/DTXtreme

Hi all,

I've bought a couple of dual trigger pads. The dual trigger cymbal & 
snare pads I've no problems with.

But the dual trigger pad for the Hi-Hat is not so cut & dry. The rim 
sound say's "Being used" and whenever I try to change the sound of 
either the rim or center pad voice, both change to the same sound. 
I've been reading the manual & trying on my own & I'm still not sure.

Any thoughts on this?

Thanks, Steve