The FR4x has an issue with Velocity MIDI out in accordion mode. It is just too weak. You have to strike the keys so hard to reach some high level of velocity. It's not realistic in actual performance. I don't have the same problem with the 7x because the 7x provides a parameter (once again in accordion mode) that affects the velocity level on midi out. So in the end, it works very well. I don't remember if I had the same issue with the 1x or the 3x.
