Yamaha DTXpress/DTXplorer/DTXtreme

The kick tower noise is not huge - but it's noticeably
louder than the rest of the pads. Some of this noise
is created by the pedal you use also, so get a quiet,
well-oiled pedal. I would estimate the noise as being
equivalent to stamping your foot on a tiled floor.
It's really more of a click than a thud.
Covering it with a bit of mouse mat or similar rubber
substance will reduce the noise considerably, but may
reduce the sensitivity. If you play the kick drum
hard, this won't bother you - but if you play flams
and jazzy stuff, you might lose a bit.
Maybe try and "damp" the actual tower itself. Some of
the noise is generated by the resonance of the metal
in the tower and some by the movement of the tower as
the beater strikes it.
Let us know if you have any success.
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