Yamaha DTXpress/DTXplorer/DTXtreme

You might want to try the DTXtreme group:

http://launch.groups.yahoo.com/group/DTXtreme/

The DTXtreme pads have a control know (as well as a volume adjustment)
and I think that is for making adjustments like snares, but I cannot
be sure.  extract from the manual:

When using a TP120SD or TP100 pad for the snare drum or
tom (connected to trigger inputs 1 to 6), you can use the pad
controller to adjust the drum tone. Specify a voice parameter
(page 48) adjusted by the pad controller. Select a value that
ends with an “R” letter, for simultaneous control for both pad
and rim 1 voices.
❏ Settings: off (no effect), pitch (R) (Tuning), volume (R), voice
(R), pan (R), layer (R), filter (R), Q (R), attack (R),
decay (R), decay R+ (see note), wave 1 (Layer 1 voice)*,
wave 2*, XSfilter*, XSdecay*, balance*
* Controllable when Type=XtrSnr is selected in voice settings.
nThe decay+R value can continuously adjust the voice decay rate and
switch to another specific voice (strainer-off tone for the snare
drum, for example) at a minimum setting.
nYou can select any parameter here, but actual effect by the pad
controller depends on the drum voice selected in the voice settings.

Keith.