keff Most welcome Keff. Touch sensitivity settings, even though I have never used them on my systems, as I use the default settings .... is basically configuring the relation between your actual key velocity (measured or estimated by your piano system) and the software velocity value that will finally determine how loud or soft your piano note will come out.
For example, suppose you play a note on one of your digi piano keys. Your piano system will make a measurement of your actual key velocity at some stage during your key strike.
If you struck the key very softly, then that would normally be expected to produce a soft or not very loud sound from the digital piano.
But ... because we have software involved, the software programmer can easily include a setting that scales up (increases) your original note velocity by some user-desired amount. This means ... if you push the key very slowly ... it is possible to configure your system to turn that slow key velocity into a much faster velocity, so that the sound coming out can be very strong and loud (even for slow key presses).
Naturally, there will be velocity range limitations. But the main idea is providing users with various choices of note velocity sensitivity is to give users some choices. Eg. some kids which haven't developed finger strength etc might need to have note velocities scaled up to provide extra oompf etc.
