@Charles Cohen ok this is where I get confused, over here you mentioned that the PX series generates velocity from 15-115 yet a high end model like the Kawai VPC1 would generate (1-127). So as many mentioned here that having dual/triple sensor have nothing to do with generating full velocity range. My question is , then what is it for which a Kawai is able to and not the Casio ?
You are making an assumption, that the VPC1 _does_ generate velocities of 1-127.
. . . Who tested a VPC1, and looked at the MIDI output,
. . . and found that it _does_ cover the full 1-127 range ?
Maybe it does, maybe it doesn't.
The Casio generates about 100 different values of velocity. That's much finer resolution than my playing. With a velocity map in my VST, I can map the lowest generated MIDI value to a very soft sound, and the largest value to a very loud sound. It happens that a straight-line map between those extreme values, works well for Pianoteq and the PX-350, and my playing.
As for "what's the difference?":
The VPC1 action feels closer to an acoustic action, than the Casio action. Just about everyone who has played both of them, agrees on that. That's one thing that all the extra money buys. The VPC1 is (I think) more rugged, and might last longer with heavy use.
On a "two-sensor" keyboard, all that the MIDI velocity does, is tell you how fast the key moved, between the top and bottom sensors.
. . . When the key moves upward, past the top sensor,
. . . the keyboard generates a "Note-off" event.
On a "three-sensor" keyboard, the MIDI velocity tells you how fast it moved between the middle sensor, and the bottom sensor.
. . . The top sensor is used to detect "key all the way up", and generate MIDI "note-off" events.
You can go crazy with all this detail.